Реферат: Н. Э. Баумана Стасенко И. В., Кальгин Ю. А обучение чтению литературы на английском языке по специальности рл6 «Основы нанотехнологии» Учебно-методическое пособие

Московский государственный технический университет имени Н.Э. Баумана


Стасенко И.В., Кальгин Ю.А


ОБУЧЕНИЕ ЧТЕНИЮ ЛИТЕРАТУРЫ НА АНГЛИЙСКОМ ЯЗЫКЕ ПО СПЕЦИАЛЬНОСТИ РЛ6

«Основы нанотехнологии»


Учебно-методическое пособие для студентов старших курсов


Издательство

МГТУ им. Н.Э. Баумана

2009

Редактор кандидат филологических наук

Труфанова Наталия Олеговна


CONTENTS















Предисловие

4

Аннотация

5

^ What is Nano-Technology?

6







Lesson 1

8

Text 1A. Introduction. Nanotechnology and nanomaterials

9

Text 1B. Nanoelectronics, nanooptoelectronics, and information nanoprocessing

12

Text 1C Size effects

15

Grammar exercises

17







Lesson 2

22

Text 2A. Introduction. Nanomaterials with 2D-nanostructures (nanolayers)

23

Text 2B. InAlGaAs layers for high electron mobility transistors

26

Text 2C. InN layers for high electron mobility transistors

29

Grammar exercises

31







Lesson 3

34

Text 3A. AlGaN/GaN heterojunction for Hall Effect sensors

35

Text 3B. CoFe/AlOx- nanolayers for magnetic tunnelling transistors

37

Grammar exercises

40







Text for rendering in English

43

Supplement text

46

Alphabetical dictionary of technical terms

56

ПРЕДИСЛОВИЕ


Целью данного учебно-методического пособия является обучение студентов старших курсов факультета РЛ точно понимать и переводить оригинальные научные тексты по специальности РЛ6 (Основы нанотехнологии).

Структура пособия обеспечивает эффективную работу студентов как самостоятельную, так и под руководством преподавателя в этом направлении.

Перед проработкой каждого текста необходимо внимательно ознакомиться с вокабуляром, содержащим терминологическую лексику. Студенты должны выучить эти термины. Знание терминологического вокабуляра создает предпосылки для дальнейшего беспереводного понимания научной литературы в этой области.

Послетекстовые упражнения подразделяются на следующие три типа:

упражнения на контроль понимания прочитанного, концентрирующих внимание на основных идеях, фактах, данных, явлениях, законах, выводах, разных точках зрения и т.д. с целью передачи точного их изложения на русском языке;

разнообразные и сложные по структуре грамматические упражнения на распознавание и перевод инфинитивных и причастных конструкций, а также на многообразные типы придаточных предложений, построены на лексическом материале данной специальности из оригинальных источников, позволяют студентам повторить и распознать, и правильно переводить грамматические конструкции в новом лексическом оформлении;

упражнения на развитие навыков аннотирования и реферирования являются самым высоким уровнем самостоятельного осмысления научной литературы на продвинутом этапе обучения студентов. Их успешное выполнение является показателем эффективности всего курса обучения и данного пособия в частности.

Алфавитный терминологический словарь в конце пособия предназначен для самостоятельной работы студентов над дополнительными английскими текстами. Дополнительные тексты и словарь можно использовать для промежуточных тестов и рубежных заданий (контрольных работ).

Тексты на русском языке нацелены на свободное их изложение на английском языке и перевод, что будет способствовать повторению и закреплению терминологической лексики, а также ознакомлению с разносторонними областями применения нанотехнологий.

Авторы пособия выражают большую благодарность доцентам Е.А. Скороходову и К.В. Малышеву за консультации при подборе текстового материала.


АННОТАЦИЯ


Учебно-методическое пособие из трех уроков, предназначенное для обучения чтению и переводу студентов старших курсов факультета РЛ, содержит современные неадаптированные тексты, отражающие основные и базисные сведения о нанотехнологиях.

Текстовый материал был рекомендован и согласован с руководством кафедры РЛ6 в соответствии с лекционным курсом по данной специальности, предусмотренным программой.

Пособие содержит упражнения на контроль понимания текстов всех трех уроков, грамматические упражнения на наиболее трудную грамматику и упражнения, подготавливающие к аннотированию и реферированию научной литературы.

Каждый текст предваряет терминологический словарь, снимающий лексические трудности. В конце пособия приводится обобщенный алфавитный словарь для удобства перевода дополнительных текстов также представленных в пособии.


Read the text without a dictionary. Give the general idea of nanotechnology.


What is Nanotechnology?

Over the past few decades, the develop­ment of new and more advanced energy technologies with the capability of improv­ing life all over the world have been sought in the fields of science and engineering. In order to make the next leap forward from the current generation of technology, scien­tists and engineers have been developing a new field of science called Nanotechnology.

Nanotechnology is defined as the sci­ence and technology of building electronic circuits and devices from single atoms and molecules, or the branch of engineering that, deals with things smaller than 100 nanome­ters. A nanometer (nm) is one billionth of a meter, roughly the width of three or four atoms. For scale comparisons, the average human hair is about 80,000 nanometers wide, and a single virus particle is about 100 nanometers in width. The prefix nano-comes from the Greek word nenos, meaning "dwarf." Scientists originally used the pre­fix just to indicate "very small," as in "nanoplankton," but it now means one-bil­lionth, just as milli- means one-thousandth, and micro- means one-millionth.

The term Nanotechnology is also often used to describe the interdisciplinary fields of science devoted to the study and use of nanoscale phenomena. (1225)

History

The story of nanotechnology begins in the 1950s and 1960s, when most engineers were thinking big, not small. This was the era of big cars, big atomic bombs, big jets, and big plans for sending people into outer space. Huge skyscrapers, like the World Trade Center (completed in 1970) were built in major cities of the world. The world's largest oil tankers, cruise ships, bridges, interstate highways, and electric power plants are all products of this era. Other researchers, however, focused on making things s nail. The invention of the transistor in 1947 and the first integrated circuit (IС) in 1959 launched an era of elec­tronics miniaturization. It was these small devices that made large devices, such as spaceships, possible.

As electronics engineers focused on making things smaller, engineers and scien­tists from other fields also turned their focus to small things - atoms and mole­cules. After successfully splitting the atom in the years before World War 11, physicists struggled to understand more about the particles from which atoms are made, and the forces that bind them together. At the same time, chemists worked to combine atoms into new kinds of molecules, and had great success converting the complex mo­lecules of petroleum into all sorts of useful plastics.

Usually the credit for inspiring nano-technology goes to a lecture by Richard Phillips Feynman, a brilliant physicist who later won the Nobel Prize for "fundamental work in quantum electrodynamics". On December 29, 1959, Feynman delivered a lecture at the annual meeting of the American Physical Society; in that talk, called "There's Plenty of Room at the Bottom", Feynman proposed work in a field "in which little has been done, but in which an enormous amount can be done in princi­ple." In his lecture Feynman described how the entire Encyclopedia Britannica could be written on the head of a pin, and how all the world's books could fit into a pamphlet. Such remarkable reductions could be done as "a simple reproduction of the original pictures, engravings, and everything else on a small scale without loss of resolution." Yet it was possible to get still smaller: if you converted all the world's books into an effi­cient computer code instead of just reduced pictures, you could store "all the informa­tion that man has carefully accumulated in all the books in the world ... in a cube of material one two-hundredth of an inch wide - which is the barest piece of dust that can be made out by the human eye."

Feynman himself didn't use the word "nanotechnology" in his lecture; in fact, the word didn't exist until 15 years later, when Norio Taniguchi of the Tokyo University of Science suggested it to describe technology that strives for precision at the level of about one nanometer. Only in the 1980s did this new field of study get a name -Nanotechnology. This new name was popu­larized by physicist K. Eric Drexler. (2905)


Nanomaterials

Nanomaterials - materials having unique properties arising from their nanoscale dimensions - can be stronger or lighter, or conduct heat or electricity in a different way. They can even change colour; particles of gold can appear red, blue or gold, depending on their size. These special attributes are already being used in a num­ber of ways, such as in the manufacture of computer chips, CDs and mobile phones. Researches are progressively finding out more about the nanoscale world and aim to use nanotechnologies to create new devices that are faster, lighter, stronger or more efficient. Nanotechnologies are widely seen as having huge potential in areas as diverse as healthcare, IT and energy storage. (707) (total – 4096)


LESSON 1


Memorize the following basic vocabulary and terminology to text 1A

unique physical phenomena – уникальные физические явления;

bulk matter – основная, исходная масса вещества;

pertain to – иметь отношение к, иметь отношение;

a realm of – область, сфера;

infinite bulk system – бесконечная внутренняя структура;

quantum dots – квантовые примеси, квантовые точки;

superlattice – сверхрешетка, кристаллическая сверхрешетка;

space structures and shapes – пространственные структуры и формы;

catalytic properties – каталитические свойства;

broad interdisciplinary research area – широкая междисциплинарная область исследования;

confinement of elementary excitation – ограничение элементарного возбуждения;

coupled finite systems – связная конечная система;

ubiquity of the phenomenon – повсеместность явления;

far-reaching potential applications – области применения c многообещающим применение;

implication on – воздействие на.


Read text 1A with its introduction and answer the questions.


Text 1A

Introduction. Nanotechnology and nanomaterials

Nanoscience and nanotechnology pertain to the synthesis, characterization, exploration, exploitation, and utilization of nanostructured materials, which are characterized by at least one dimension in the nanometer (1 nm = 10–9m) range.

A focus of frontline interdisciplinary research today is the development of the conceptual framework and the experimental background of the science of nanostructured materials and the perspectives of its technological applications. The implications of quantum size and shape effects on the energetics, nuclear–electronic level structure, electric-optical response and dynamics, reveal new unique physical phenomena that qualitatively differ from those of the bulk matter and provide avenues for the control of the function of nanostructures. Current applications in the realm of nanoelectronics, nanooptoelectronics, and information nanoprocessing are addressed, and other directions highlighted.


^ Nanostructures and their ensembles


Nanostructured systems constitute a bridge between single molecules and infinite bulk systems. Individual nanostructures involve clusters, nanoparticles, nanocrystals, quantum dots, nanowires, and nanotubes, while collections of nanostructures involve arrays, assemblies, and superlattices of individual nanostructures. Table 1 lists some typical dimensions of nanomaterials.

Table 1. Nanostructures and their assemblies


Nanostructure

Size

Material

Clusters

Radius: 1–10 nm

Insulators, semiconductors, metals, magnetic materials

Nanocrystals

Quantum dots

Other nanoparticles

Radius: 1–100 nm

Ceramic oxides

Nanobiomaterials

Radius: 5–10 nm

Membrane protein

Photosynthetic reaction center

Nanowires

Diameter: 1–100 nm

Metals, semiconductors, oxides, sulfides, nitrides

Nanotubes

Carbon, layered chalcogenides

Nanobiorods

Diameter: 5 nm

DNA

2D arrays of nanoparticles

Area: several nm2–µm2

Metals, semiconductors, magnetic materials

Surfaces and thin films

Thickness: 1–1000 nm

Insulators, semiconductors, metals, DNA

3D superlattices of nanoparticles

Radius: several nm

Metals, semiconductors, magnetic materials


The conceptual framework and practice of nanoscience encompasses both nanostructures and their ensembles. In this broad context, the physical and chemical properties of nanostructures are distinct from both the single atom or the molecule and from the bulk matter of the same chemical composition. These fundamental differences between the nanoworld on the one hand, and the molecular and condensed phase worlds on the other hand, pertain to the spatial structures and shapes, phase changes, energetics, electronic–nuclear level structure, spectroscopy1, response, dynamics, chemical reactivity, and catalytic properties of large, finite systems and their assemblies. Central issues in this broad, interdisciplinary research area of nanoscience pertain to size effects, shape phenomena, confinement of elementary excitations, level structure of elementary excitations, and the response to external electric and optical excitations of individual finite systems and of coupled finite systems. The ubiquity of these phenomena reflects on quantum effects in finite nanostructures. (2795)


^ Answer the following questions:

1) What does nanoscience and nanotechnology pertain to? 2) Does the physical phenomena in nanomaterials differ from the ones in the bulk matter? What way? 3) What can an individual nanostructure involve? 4) What does the fundamental difference between the nanoworld and the molecular and condensed phase worlds lie in? 5) What does the interdisciplinary research area of nanoscience pertain to? 6) How do you understand the terms spectroscopy and spectrometry? Suggest their fields of application.


Task 1. Comment on table 1 with its nanostructures and their assemblies.

Task 2. Discuss the issues of interdisciplinary research area of nanoscience, and nanostructured materials and the perspectives of their application

Task 3. Make up the presentations on the issues mentioned in exercise 2 in Power Point


Memorize the following basic vocabulary and terminology to text 1B


be fraught with – быть сопряженным с;

surface-nanodevice chemical contacts – химические контакты с поверхностным нанослоем;

be aimed to/towards – направленный на, преследовать цель;

Coulomb blockage2 – Кулоновская блокада;

scanning probe tips in arrays – концы многоэлементного датчика для сканирования (поверхности);

LED – светодиод (Light Emitting Diode)

stepwise burning of layers – поэтапный выжиг слоев;

chirality control – хиральное управление (отсутствие зеркальной поверхности);

to allow for – предусматривать, учитывыать;

Y junction nanotubes – соединенные по вертикали нанотрубки;

confinement – удержание, сдерживание;

bottom-up approach – принцип восходящего анализа (от простых элементов к сложным);

top-down approach – принцип нисходящего анализа (от сложных элементов к простым);

resonant tunneling devices – устройство с резонансным туннелированием;

multivalued logic – многозначная логика, многозначные логические схемы;

supramolecular chemistry – супрамолекулярная химия;

spintronic3 memory – магнитоэлектронная память;

promising direction – многообещающая область (науки).


Read text 1B and answer the questions after the text

Text 1B

Nanoelectronics, nanooptoelectronics, and information nanoprocessing

One of the most important and far-reaching potential applications of nanomaterials will be in the field of nanoelectronics. While the field of molecular electronics was fraught with some conceptual–practical difficulties in the context of connecting molecular devices to the “outside world”, these issues were solved by nanodevice fabrication, the design of surface-nanodevice chemical contacts, and chemical engineering of molecular-nanoparticles or biomolecular-nanoparticle hybridization. This multidisciplinary research–technology area of nanoelectronics has dual goals:

The utilization of a single, individual nanostructure (e.g., cluster, nanoparticle, nanocrystal, quantum dot, nanowire, or nanotube) for the processing of optical, electrical, magnetic, chemical, or biological signals.

Providing nanostructured materials, consisting of assemblies of nanostructures, for electronic, optoelectronic, chemical-catalytic, or biological-diagnostic applications.

The distinction between classes (1) and (2) is always practical and sometimes also conceptual. While class (2) is aimed toward the miniaturization of electronic circuitry and of catalytic and biological templates, class (1) is aimed toward the realization of single-electron nanodevices. There are already significant advances in the utilization of single nanostructures for single-electron memory devices based on Coulomb blockade and on a single-electron transistor. Progress for the class (2) system involves scanning probe tips in arrays, LED and laser diodes of semiconductor nanostructures, arrays of semiconductor quantum dots, and nanowires. Nanocircuits making use of carbon nanotubes were described. Metallic and semiconducting properties of multiwalled nanotubes have been constructed by the stepwise burning of layers and by chirality control. These approaches allow for the use of nanotubes in nanocircuitry, with special potential advances in the use of Y junction nanotubes. Another significant area involves nanomaterials for optoelectronics, where functional devices, based on confinement, low potential for photonic switching and optical communication.

The information paradigm in nanostructures may involve two alternative routes. First, the bottom-up approach, starting from a single nanostructure being based on nanofabrication, miniaturization, and assembly of nanostructures to produce a nanostructured computer. Resonant tunneling devices deserve special mention in this context, since they have already demonstrated success in multivalued logic and memory circuits. Second, the top-down approach will utilize and apply the conceptual framework of supramolecular chemistry and self-assembly of nanostructures to produce organized suprastructures for information processes. Spintropic memory based on magnetic, semiconducting nanoparticles, provides a promising direction. (2564)


^ Answer the following questions:

1) Why is the field of electronics one of the most important and far-reaching potential applications? 2) What are the dual goals of multidisciplinary research-technology area of nanoelectronics? 3) How do you understand the term Coulomb blockage and how is it used in physics? 4) What are the advances in the utilization of single nanostructures? 5) What do the stepwise burning of layers and chirality control allow for? 6) Why do resonant tunneling devices deserve special mention in the context of nanostructured computers?


Task 1. Put your own questions to the text. Discuss the questions with the group. Provide the group with some additional information on issues of the lesson.

Task 2. Look through the text and find the sentences that refer to potential applications of nanomaterials and their advances.

Task 3. Look through the text again and give the main idea of the distinction between goal classes (1) and (2).

Task 4. Find the paragraph discussing the information paradigm in nanostructures. Explain what two alternative routs it may involve.

Task 5. Use internet to find more material about nanoelectronics, nanooptoelectronics, and information nanoprocessing. Summarize the material and be ready to tell the group about it in brief or give a presentation in Power Point.


Memorize the following basic vocabulary and terminology to text 1C


quantification – определение количества;

fall into two categories – разделяться, распадаться;

moderately sized clusters and nanostructures – кластеры и наноструктуры средних размеров;

irregular variation of the relevant property χ(n) – беспорядочное изменение значимого свойства χ(n)

in terms of the size equation – выраженное в уравнении размеров;

scaling law – правило масштабирования;

nuclear adiabatic dynamics – ядерно-адиабатическая динамика;

novel fragmentation pattern – новая модель разделения;

cluster fission and Coulomb explosion – разделение на кластеры и кулоновский взрыв;

multicharged single clusters – многозарядный единичный кластер.


Read text 1C and answer the questions after the text.


Text 1C

Size effects

A key concept for the quantification of the unique characteristics of individual nanostructures pertains to size effects. These involve the evolution of structural, thermodynamic, electronic, energetic, spectroscopic, electromagnetic, dynamic, and chemical features of finite systems with increasing size. This concept emerged from cluster chemical physics, but is applicable to other nanostructures (e.g., nanocrystals or nanowires). Size effects fall into two categories 1) Specific size effects. These involve self-selection and existence of “magic numbers” for small and moderately sized clusters and nanostructures. An irregular variation of the relevant property χ(n) (where n is the number of constitutents), with increasing the size of the nanostructure, is manifested. 2) Smooth size effects for “large” nanostructures. In this size domain, a quantitative description was advanced for the “transition” of the physical and chemical attributes of clusters to the infinite bulk system in terms of the size equation X(n) = X(∞) + Cn–a, where C is the constant and a (a≥ 0) is a positive exponent.

Size equations constitute scaling laws for the nuclear-electronic level structure, energetics, and dynamics, providing the quantitative basis for the description of optical and electrical response of nanostructures. Nuclear adiabatic dynamics of clusters manifests new collective excitations, (e.g., compression modes), which do not have an analog in the bulk. Finite systems exhibit novel fragmentation patterns, such as cluster fission and Coulomb explosion, which are unique for finite systems and do not have an analog in the dynamics of the corresponding bulk matter. A striking example constitutes the dynamics of Coulomb explosion of multicharged single clusters, which may also prevail in nanostructures, whose energetics is characterized by a divergent scaling size equation. (1627)


^ Answer the following questions:

1) What do the size effects involve? 2) What are the two categories the size effects fall into? 3) What was the quantitative description advanced for? 4) What do size equations constitute? 5) What do finite systems demonstrate?


Task 1. Explain the concept “size effect” in your own words the way you understand it.

Task 2. Look through the text again and explain concept “the quantification of the individual nanostructure characteristics”.

Task 3. Remember Latin contractions such as e.g., i.e., et. al., viz., etc and many others. Learn how to read them in Latin and give their English equivalents. Use them in your own examples.

Task 4. Write an abstract on the text. Please remember that an abstract is a secondary document telling a reader what the text is about and does not give any details. Compare and discuss you abstract with a partner.


Grammar exercises for lesson 1

Exercise 1. Specify syntactic functions of Infinitives in the following sentences and translate them accordingly.

To produce workable EMR (extraordinary magneto resistance) nanostructure was the demand of dramatic changes in optoelectronics.

To produce workable EMR nanostructure, the university research team invited some world – famous physicists.

To understand such physical effect as extraordinary magnetoresistance (EMR), we shall consider the device shown on the next page.

To understand such physical effect as EMR is very important for our further research.

To form the strongest material known was a hard and time consuming task.

To form the strongest material known, nanotubes are combined, and yet they are both lightweight and transparent.

To explain this phenomenon, one has to study how the electrons actually travel along random paths.

To explain this phenomenon to people who have no idea of physical laws was rather difficult.

To reduce the weight of cars and spacecrafts dramatically, designers will use carbon nanotechnology more and more widely.

To reduce the weight of cars and spacecrafts dramatically will be the main result of their promising research they have been doing for so many years.

To demonstrate, what shape the electric field lines take, was one of the purposes of his presentation.

To demonstrate, what shape the electric field lines take, he prepared several slides for his presentation.


Exercise 2. Determine syntactic functions of Infinitives in the following sentences and translate them.

Richard Feynman was the first who predicted the election-beam lithography. The latter is used today to make silicon chips. We know him to be awarded the Nobel Prize in 1965 for his contribution to quantum electrodynamics.

Ralf Landauer, a theoretical physicist, was one of the first who realized the importance of quantum mechanics effects on the development of nanoelectronics.

Nanomaterials to be used in nanoelectronics must consist of assemblies of nanostructures workable in different optoelectronics and other devices.

The task to reduce the weight of cars and spacecrafts seemed to be feasible in the near future.

Two Russian scientists Ekimov and Omushchenko were the first who observed quantum confinement.

The equation to be remembered describes a system oscillating with certain frequency and amplitude.

Richard Feynman predicted the appearance of silicon chips to be produced by electron-beam lithography.

After thorough study of nanotechnologies and nanomaterials the next chapter to be read is “Nanowires and Nanotubes”.

A new type of a battery to be built in with the other circuitry on a clip was called a nanobattery.

Exercise 3. Find Complex Object Infinitive in the following sentences and translate them.

Scientists know this superlattice to possess very interesting electrical properties.

David Tomanek, a professor of physics at Michigan State University, considers each of the nanotube forms to find applications for which they are best suited.

Since their discovery in 1991, researchers believed carbon nanotubes to be the most important candidates to dominate the 21st century revolution.

They assumed the extraordinary magnetoresistance (EMR) effect to work by changing the paths of electrons travelling through the device.

Manufacturers of optoelectronics device expected scientists to obtain considerably greater magnetoresistance (MR) from a nonmagnetic metal such as gold.

We supposed them to be studying the properties of microelectronic structure called a semiconductor superlattice.

The researchers believed magnetoresistance to be the phenomenon in which the electrical resistance of a metal or a semiconductor increases or decreases in response to magnetic field.

Physicists found the very much larger effect of EMR to depend on the magnetic field curving the electrons paths.

The above mentioned effect causes the electric field lines to curve inward and concentrate on the metallic disk.

The current is thus tunneled through the highly conductive metal which causes the device as a whole to have a low resistance.

Customers might see the magnetoresistance (MR) sensors used in banks do currency sorting and counting based on magnetic inks.

The discovery and study of MR phenomena enabled scientists to develop magnetic sensors and EMR sensors in particular. The latter are supposed to have myriad potential applications.

We known EMR sensors to be used now in magnetic-field testing for machinery and engines, speed sensing for gears, position-sensing robots for factory production lines to name but a few.

Computer experts know disk drives to have three key components: the magnetic disk medium to store the information, the write-head element to write information onto the disk, and the read-head element to read the information. All three components will have to be improved considerably to satisfy the demand for low-cost, high-speed storage at ever greater densities.

The design of the nanobattery enables it to lie inactive for at least 15 years, but then it is capable of waking up and immediately providing a burst of high energy.

Not only does nanotechnology enable structures to be made much smaller. It also enables effects that are not visible on larger structures to be utilised. Researchers found the material to exhibit different electromagnetic or optical properties on these scales as a result of atomic sizes involved. This opens tremendous opportunities to be exploited in many different ways.

Exercise 4. Point out Complex Object Infinitive constructions in the following sentences and translate them accordingly.

Nanophysics is known to deal with physical effects at the nanometer and sub-nanometer scale.

Semiconductor superlattice is known to consist of layers stacked like a sandwich.

Sensors based on nanotechnology are likely to revolutionize health care, climate control and detection of toxic substances.

One of the most important and far-reaching potential applications of nanomaterials is certain to be in the field of nanoelectronics.

Nanophysics is reported to include physical laws applicable from 100 nm scale down to the sub-atomic, sub-0.1 nm scale.

A knowledge of processes related to the nanoscale structures is likely to be helpful in developing technologies for preventing or minimizing harm to the environment.

Metallic and semiconducting properties of nanotubes are reported to have been constructed by a special method.

Research focused on one phenomenon happened to result in the unexpected discovery.

Nanostructred systems are considered to constitute a bridge between single molecules and infinite bulk systems.

Dozens of research teams across the globe are now assumed to be working to develop robust nanoscale electrical switches based on atoms or molecules.

Size equations proved to constitute scaling laws for the nuclear electronic level structures and dynamics.

Gregory Snider, currently a consultant with Hewlett-Packard Laboratories in Palo Alto, Calif, is said to be exploring ways to improve the architectural design of nanoelectronics.

Stanley Williams, the director of Quantum Science Research (QSR) program at Hewlett Packard Laboratories, is reported to guide the multidisciplinary team that designs, builds and tests new nanocircuits. His primary interests now are said to be focused on the study of intersection of nanoscience and information technology.

In our case, demultiplexer is known to be a special type of a crossbar in which many nanowires connect to a small number of conventional wires.

A big problem is sure to occur, however, if one of the connections between a nanowire in the multiplexer and a conventional wire is broken.

This team of researchers is believed to have found the way to protect nanowires from broken connections in the demultiplexer.

In the case considered, each nanowire happened to have several broken connections to the conventional wires.

The field of nanoscale fabrication is said to be extremely active today, with many competing techniques being under study.

Bruce Gnade and William Warren are reported to have recognized that effective architecture was critical for developing the new nanoscale device technologies.

The scanning tunneling microscope (STM) is known to produce real-space imaging of atomic dimensions. It (STM) is reported to have been designed to study atomic structure of thin films.

Magnetoresistance proved to be the phenomenon in which the electrical resistance of a metal or a semiconductor increases or decreases in response to a magnetic field.


LESSON 2


Memorize the following basic vocabulary and terminology to text 2A


abundant new physics – многочисленные новые физические процессы, явления;

Molecular Beam Epitaxy – молекулярно-пучковая эпитаксия

atomic precision – атомарная точность;

adjacent quantum wells – смежные квантовые ямы;

lateral modulation – поперечная модуляция;

band structure – зонная струтура;

lithographically defined top gates – верхний затвор, полученный литографическим способом;

Brillouin zone4 – зона Бриллюэна;

Fermi energy5 – энергия Ферми;

inherent inadequacy of lateral modulation schemes – присущее несоответствие поперечной схемы модуляции;

produce concurrently – изготавливать параллельно, согласовано;

cleaved edge overgrowth technique – метод выращивания на сколотой грани;

unprecedented precision – беспрецедентная точность;

in situ – непосредственно, в момент образования, по месту;

heterointerface – граница раздела в гетеропереходе;

finite overlap – полное перекрытие, наложение;



Read text 2A with its introduction and answer the questions.
^ Text 2A Introduction. Nanomaterials with 2D-nanostructures (nanolayers)
2D-nanostructures are structures like layers, having large (near 1 μm) sizes on two coordinate axes, and nanometer size on third axe.


Lateral AlGaAs- superlattice


Abundant new physics was brought about by the invention of the superlattice (SL) concept and its subsequent realization through molecular beam epitaxy (MBE) of layered semiconductor structures with atomic precision. The formation of minibands isolated by minigaps in the vertical SL direction ensues from the coupling between adjacent quantum wells. In order to reduce the dimensionality of the system, electrons are confined in one direction to a quantum well, and a lateral periodic potential modulation may additionally be imposed from the surface of the sample with, for example, lithographically defined top gates. As in the conventional vertical SL geometry, an artificial band structure derives from the reduced width of the Brillouin zone and zone folding. Magnetotransport offers an excellent tool for the study of the resulting band structure in these laterally modulated two-dimensional systems (2DES), since oscillations in the magnetoresistance provide immediate information on the area encircled by closed electron orbits at the Fermi energy EF. Such experimental evidence for an artificial band structure is sparse. Only very recently, using two-dimensional modulation, unambiguous proof of two different closed electron orbits was achieved. This lack of evidence may be related to the inherent inadequacy of lateral modulation schemes in producing concurrently a high quality 2DES and a sufficiently short period and large amplitude modulation to guarantee the occupation of only few, well-isolated minibands.

We use a new concept to fabricate lateral SLs based on the cleaved edge overgrowth technique, that overcomes the limitations of previous geometries by periodically modulating the material composition directly adjacent to the 2DES. In this way, both the period and the modulation strength can be tailored with unprecedented precision by MBE growth. In a first MBE step, an undoped SL with lattice constant d=100 nm of 30 periods of 50 nm GaAs and 50 nm Al0.32Ga0.68As is grown between two n-GaAs contacts, that act as source and drain. In a second MBE step, the sample is cleaved in situ and immediately thereafter overgrown by a 30 nm undoped GaAs layer, a 100 nm AlAs barrier, and an n-GaAs gate contact. By applying a positive gate voltage with respect to source and drain a 2DES is induced at the GaAs/AlAs heterointerface. The finite overlap of the electron wave function with the SL causes a modulation of the electron density ns in x direction with a strength that depends on the GaAs layer thickness. For our sample this variation of the density, integrated over the z direction, exceeds 10%, as determined by a self-consistent 2D-Poisson/Schrödinger calculation. (2474)


^ Answer the following questions:

1) What is a 2-D nanostructure? 2) How was the new physics brought about? 3) In what way was the dimensionality of the system reduced? 4) Why does magnetotransport offer an excellent tool for the study of the resulting band structure in laterally modulated 2DES? 5) What was the difficulty in understanding of the resulting band structure in laterally modulated two-dimensional systems? 6) Why is a new concept to fabricate lateral SLs based on the cleaved edge overgrowth technique?


Task 1. Look through the text again carefully and explain the difficulty in understanding of the resulting band structure in laterally modulated two-dimensional systems?

Task 2. Describe the process of the lateral SL fabrication in detail and draw the picture of the process in a stepwise manner.

Task 3. Use your background knowledge of physics and the information given in the text to explain the terms Brillouin zone and Fermi energy.

Task 4. Use Internet to find more information about the new concept on super lattice fabrication and present it.

Task 5. Give the summary of the text mentioning the process of the lateral SF fabrication.


Memorize the following basic vocabulary and terminology to text 2B


heterojunction – неоднородный переход в полупроводниковом приборе, гетероструктурный переход;

intrinsically limited by optical photon scattering – по своей природе ограничен оптическим рассеянием фотонов;

electron density – плотность электронов;

enhance channel conductivity – повысить проводимость в канале;

conduction band – смещение зоны проводимости;

metallographic vapor phase epitaxy – металлографическая эпитаксия из паровой фазы

electron sheet density – пленочная плотность электронов;

subband occupancy – заселенность в подзоне;

electro charge distribution – распределение заряда электронов;

quantum wells (QW) – квантовые ямы;

intersubband scattering – внутреннее рассевание в подзоне;

light-induced destruction – разрушение вызванное светом

charge correlation – зарядовая корреляция (взаимосвязь);


Read text 2B and answer the questions after the text


Text 2B

InAlGaAs layers for high electron mobility transistors


Mobility of carries in quasi two-dimensional electron gas (2DEG) formed at a semiconductor heterojunction is intrinsically limited by optical phonon scattering at room temperature. For high performance devices, an increase in electron density leads to enhanced channel conductivity. The existence of DX centers in AlxGa1–xAs (x>0.22) restricts the use of a high Al mole fraction in AlxGa1–xAs /GaAs heterostructures. The small conduction band offset in such structures limits the electron density below 1012 cm–2. Owing to larger conduction band offset the pseudomorphic GaAs/InxGa1–xAs/AlyGa1–yAs quantum wells (QWs) have attracted much interest in high-speed devices. The best samples of those structures with very high 2DEG mobilities are usually grown by molecular beam epitaxy (MBE). Recent progress in metalorganic vapor phase epitaxy (MOVPE) has led to growth of high quality heterostructures. Additionally, δ-doping increases the electron density and mobility of 2DEG in the QW, and consequently improves device performance.

GaAs/In0.2Ga0.8As/Al0.2Ga0.8As QW grown by MOVPE at 630 °C and consisted nominally of 600 nm GaAs buffer layer, followed by 90 nm of (5 nm Al0.2Ga0.8As/5 nm GaAs) superlattice, 310 nm of 205 nm GaAs top barrier. The Si δ-doping (nD=2.3*1012 cm–2) was placed 10 nm from the QW in the back Al0.2Ga0.8As barrier. Similar δ-doping was applied 2 nm below the structure surface in order to saturate the surface states.

The high electron mobility 2DEG was formed in the investigated structure with no significant parallel conduction. Nonmonotonic dependence of both transport and quantum mobilities on electron sheet density was observed with the maximum related to the onset of the upper subband occupancy. An apparent increase of the quantum mobility was explained by the ionization of deep centers in the top barrier which changed the QW from asymmetric to the more squarelike. The resulting shift of the electron charge distribution away from the δ-layer leads to an increase of electron transport mobility in the QW. An explanation of the quantum mobility decrease after the upper subband occupation is less straightforward. The intersubband scattering presumably present in this density region has the opposite effect on the quantum mobility than the more effective remote charge screening. Moreover a light-induced destruction of charge correlations may be important. (2090)


^ Answer the following questions:

1) Why is the mobility of carriers in quasi two-dimensional electron gas intrinsically limited? 2) Why did pseudomorphic quantum well attract much interest in high-speed devices? 3) What is the technique to obtain the structures with very high 2DEG mobilities? 4) How was an apparent increase of the quantum mobility explained? 5) What leads to the increase of electron transport mobility in the quantum well?


Task 1. Use your background knowledge and explain the need for high electron mobility transistors. How was it achieved?

Task 2. Explain the structure of GaAs/In0.2Ga0.8As/Al0.2Ga0.8As quantum well and draw a stepwise scheme of its growth by metalogranic vapor phase epitaxy.

Task 3. Look through the second part of the text carefully and explain the characteristics of the high quality heterostructure.


Memorize the following basic vocabulary and terminology to text 2C


inherent property – внутреннее свойство;

increase luminescence efficiency considerably – значительно увеличить выход люминесценции;

saturation velocity – скорость насыщения;

wurtzite6 – вюртцит;

Monte Carlo method7 – метод Монте Карло (совокупность математических методов, позволяющих найти желаемое решение путем статистических испытаний, выполняемых, как правило, при помощи ЭВМ)

drift velocity – скорость смещения, дрейфа;

superior characteristics – более высокие характеристики;

overshoot velocity – скорость проскакивания;

field effect transistor – транзистор, управляемый полем;

cutoff frequency – предельная частота;

high-speed high-performance heterojunction – высокоскоростной высокоэффективный гетеропереход;

pulsed laser deposition technique – метод осаждения импульсным лазером;

impurity – примесь;

Hall mobility – холловская подвижность, подвижность зарядов;

molar ratio – молярная концентрация; мольное отношение;

enhanced decomposition – повышенное (усиленный) разложение, распад;


Read text 2C and answer the questions after the text


Text 2C

InN layers for high electron mobility transistors

Developments in the field of III-nitride (InN, GaN, and AlN) semiconductors have been spectacular due to their highly attractive inherent properties. During the last few years the interest in the InN has been remarkable. Recent results indicate that the InN films almost meet the requirements for application to practical devices. The development in blue/ultraviolet (UV) light emitting diodes (LEDs) and laser diodes (LDs), and also high-frequency transistors operating at high powers and temperatures has proved the benefits of the nitride materials system. Indium nitride (InN) is an important III-nitride semiconductor with many potential applications. The use of InN and its alloys with GaN and AlN makes it possible to extend the emission of nitride-based LEDs from ultraviolet to near infrared region. For example, along with GaN, the InN ternary alloy, InGaN, has found application in a variety of heterostructure based optoelectronic devices, such as LEDs and lasers. The InGaN quantum wells are indispensable for light emitting devices because incorporation of small concentrations of In in the active GaN layer increases luminescence efficiency considerably.

InN was predicted to have lowest effective mass for electrons in all the III–nitride semiconductors, which leads to high mobility and high saturation velocity. The theoretical maximum mobility calculated in InN and GaN at 300 K are about 4400 and 1000 cm2/(V*s), respectively, while at 77 K the limits are beyond 30 000 and 6000 cm2/(V*s), respectively. The electron transport in wurtzite InN was studied using an ensemble Monte Carlo method. It was found that InN exhibits an extremely high peak drift velocity at room temperature. The saturation velocity is much larger than that of gallium arsenide (GaAs) and gallium nitride (GaN).

InN achieves the highest steady-state peak drift velocity: 4.2*107 cm/s. This contrasts with the case of GaN, 2.9*107 cm/s, AlN, 1.7*107 cm/s, and of GaAs, 1.6 *107 cm/s. It was concluded that the transport characteristics of InN are superior to those of GaN and GaAs, over a wide range of temperature from 150 to 500 K and a doping concentration up to 1019 cm–3. The transport characteristics were shown to be relatively insensitive to variations in temperature and doping concentration, unlike GaAs. This suggests that there may be distinct advantages offered by using InN in high frequency centimeter and millimeter wave devices.

The transient electron transport, which is expected to be the dominant transport mechanism in submicron-scale devices, was also studied in InN. It is found that an InN exhibit the highest peak overshoot velocity and that this velocity overshoot lasts over the longest distance when compared with GaN and AlN. It was predicted that InN-based field-effect transistors (FETs) have an extremely high speed with a cutoff frequency of over 1 THz for 0.1 mm gates. Thus, InN is a highly potential material for the fabrication of high-speed high-performance heterojunction FETs.

As-grown InN is always n-type with a very high background carrier concentration-an observation similar to GaN before better doping control of that material was achieved. However, there is only one report of p-type InN grown by the pulsed laser deposition (PLD) technique, which to date has never been reported in as-grown InN film or even intentionally doped InN film. There has been much speculation as to what species is responsible for high background donor concentration in the grown InN. Theoretical calculation as well as experimental result gives conflicting views and opinions regarding the major reason responsible for such high n-type conductivity. The potential candidates for such high background donors are native defects, such as N vacancy, nitrogen antisite, and impurities, such as ON, SiIn , and possibly interstitial H. According to the oldest and common view, the nitrogen vacancy is the most probable reason for n-type conductivity of InN.

Selection of GaN for the underlying layer and increased InN film thickness significantly improve the Hall mobility. A Hall mobility of about 700 cm2/(V*s) was obtained in the InN film grown on GaN even at an electron concentration of 5*1019 cm–3. A high NH3/trimetilindium (TMI) molar ratio and enhanced NH3 decomposition (by growth temperature, atmospheric pressure growth, reduced flow velocity, etc.) significantly improved the electrical properties of MOVPE grown InN film. As a result, a carrier concentration in the order of 1018 cm–3 was obtained and the highest electron mobility obtained was 730 cm2/(Vs). These are the best electrical properties ever achieved in the MOVPE grown InN film. (3989)


^ Answer the following questions:

1) Why have the developments of III-nitride semiconductors been spectacular? 2) What do recent development results indicate? 3) What proved the benefits of the nitride material system? 4) What is the application of the III-nitride semiconductor? 5) Why are the InGaN quantum wells indispensable for light emitting devices? 6) What was found by the ensemble Monte Carlo method? 7) What do the highest steady-state peak drift velocity and relatively insensitive transport characteristics suggest? 8) What was found while studying InN transient electron transport mechanism? 9) Why do the experimental results give conflicting views and opinions? 10) Due to what factors was the highest electron mobility obtained?


Grammar exercises

Exercise 1. Translate the following sentences paying attention to Participle Constructions in different syntactic functions.

A metal disk implanted in the semiconductor distorts the electric field lines.

Implanted in the semiconductor, a metal disk distorts the electric field lines.

Spintronic memory being based on magnetic, semiconducting nanoparticles can be used in the future to produce nanostructured computer.

Being based on magnetic, semiconducting nanoparticles, spintronic memory provides a promising direction to a nanostructured computer.

A voltage applied across the ends of a semiconductor slab (пластина) sets up an electric field.

If applied across the ends of a semiconductor slab, a voltage sets up an electric field, the latter causing randomly moving electrons to drift along the slab.

The concept of photonic crystals having been theoretically formulated was used later to produce the first photonic crystal.

The concept of photonic crystals having been theoretically formulated, the first photonic crystal was fabricated much later.

Scientists created new nanomaterials, the latter having tunable electronic properties. The properties of these new nanomaterials being strongly dependent on their location along the nanotube, these new nanomaterials are believed to have far-reaching prospects to design single-molecule devices.

The properties of nanomaterials being strongly dependent on their location along the nanotube make these materials suitable for single-molecule devices.

Exercise 2. Point out Adverbial Participle constructions and Absolute Participle constructions in the following sentences, translate them accordingly.

If tested successfully, this particular vibration isolation will be adequate for the modern hardware developed recently.

Being one of the best known solid–state devices, the Hall Effect sensor is still attracting considerable attention of scientists.

The temperature increasing, no degradation of the sensor is observed.

Structural approaches of nanotechnology facilities having been discussed, scientists came to the conclusion that nanotechnology requires extremely stable environment.

Being based mainly on silicon or semiconductors, the conventional Hall Effect sensors have a remarkably low cost.

Vibration environments having been explored, researches could provide manufactures with advanced nanotechnology.

Environment permitting, nanomechanisms will work almost perfectly under these conditions.

The needs of the users having been correctly assessed, nanotechnology designers focused their attention on good vibration environments.

Though situated in a relatively quiet location, the equipment still needed a reliable internal vibration isolation.

If developed, new technologies will be used for measuring nanoscale forces and dimensions.

Appropriate nanotechnology criteria having been specified due to thorough research, scientists cannot always incorporate them in nanotechnology facilities.

Being successfully used in memory circuits, resonant tunneling devices deserve special attention in the context of this report.

The field lines and the current flow being concentrated through the metal disk, the more current flows through the device than when the disk is absent.

Gold disks were embedded in one-millimeter-radius disks, the gold disks being about 1.5 microns thick.

The size of a bit of information on a magnetic disk being reduced to increase storage density, the sensitivity of read-head must also increase.

Being fabricated from nonmagnetic materials, the read heads would not suffer from magnetic noise limitations.

Discovered in Japan, carbon nanotubes are divided into two basic types: single-walled nanotubes (SWNTs) and multiwalled nanotubes (MWNTs).

Being hollow, nanotubes are lightweight, transparent to visible light and are excellent conductors of electricity.

Though first demonstrated in nanotube transistors in the late 1990, nanotubes were first commercially used as structural reinforcements in composites and in lithium-ion batteries.

The temperature rising from absolute zero to 78000 K, disintegration of a double-wall nanotube happens.

Made of structures designed at the molecular level, DNA (deoxyribonucleic acid) machines with moving parts could be employed as nanomechanical sensors, switchers as well as for more elaborate robotic functions.

Environmental vibration being reduced, the images produced by the scanning tunneling microscope (STM) become much better.


LESSON 3

Memorize the following basic vocabulary and terminology to text 3A

Hall effect sensors – датчики Холла; датчики, работа которых основана на явлении Холла;

proximity switches – бесконтактный переключатель;

harsh environmental conditions – суровые природные условия;

heterojunction – гетеропереход;

band gap – запрещенная зона;

intrinsic carriers – собственные носители заряда;

elevated temperatures – повышенная температура;

to sacrifice in mobility – снижение подвижности;

breakdown voltage – напряжение пробоя;

sheet carrier densities – пленочная плотность заряда;

residual charge – остаточный заряд;

annealed contacts – отожженные контакты;

to dice – нарезать кристаллы из полупроводниковой пластины;

biasing current – ток смещения, ток подмагничивания;

linear regression fitting technique – метод линейно-регрессионного приближения;


Read text 3A and answer the questions after the text

Text 3A

AlGaN/GaN heterojunction for Hall Effect sensors

Hall effect sensors are widely used as proximity switches, position sensors, velocity sensors, and in current sensing applications. Although it is one of the best known solid-state devices, the Hall effect sensor is still attracting considerable attention. One of the areas of interest is to enable Hall effect sensors to function at high temperatures (>250 °C) and other harsh environmental conditions; those operating