Make sentences from the words in brackets using the Present Perfect Passive.

1. I have always wanted to travel through time. (But/time/machines/not/invent/yet).

2. We are looking for the place to see some interesting events. (Minsk-Arena/build/as a/high-technology/complex/to/hold/the/competitions/

and/concerts/of/world/level).

3. Not only tests help us to obtain objective results. (This/theory/also/use/for/analyzing/the/experimental/data).

4. Today’s mobile connection looks fantastic. (Many/different/devices/create/in/order/to/improve/the/performance/of/communications).

5. Physicists think that Newton’s laws are the main laws of nature, but chemists object that …

(Mendeleev’s/periodic/law/accept/as/a/universal/law/of/nature).

10. Form adjectives from the following nouns using the suffix -ous and translate them.

For example: advantage – преимущество;

advantageous – преимущественный.

Analog, danger, oxygen, hydrogen, phosphorus, cobalt.

11. Read and translate word-combinations.

A. start from the first component

1. atmospheric geological operatingconditions static room	3. absolute vibratory orbitalmovement free spherical
2. operating starting zero closedposition fixed angular (угловой)	4. electromagnetic acoustic electric gravitationalfield magnetic sinusoidal vector

B. start from the second component

1. electron energy airflow fluid radiation current

2. arsenic germanium aluminiumnucleus copper silicon selenium

12. Match the following sentences with their translations.

1. Do holes really move? 2. Recombination has occurred and a hole has disappeared. 3. If no voltage is applied to the crystal, the movement of both holes and electrons is quite random. 4. Was this caused by heating? 5. The effect is as though a hole has moved from point A to point C. 6. If some voltage is applied, then the electrons will begin to move in one direction, and the holes will begin to move in the opposite direction. 7. Under the same conditions (the increase of temperature by one degree Centigrade) the conductivity of silicon will increase by 7 per cent. 8. Can we say that both electrons and holes are charge carriers? 9. The problem of the movement of holes has been completely considered.

a. Это было вызвано нагреванием? b. Проблема перемещения дырок была полностью рассмотрена. c. При тех же условиях (увеличение температуры на один градус Цельсия) проводимость кремния увеличится на 7%. d. Произошла рекомбинация, и дырка исчезла. e. Можем ли мы сказать, что носителями зарядов являются и электроны, и дырки? f. Если никакого напряжения не приложено к кристаллу то движение как дырок, так и электронов совершенно хаотическое. g. Эффект такой, будто бы дырка переместилась из точки A в точку C. h. Действительно ли дырки движутся? Если приложить какое-то напряжение, тогда электроны начнут двигаться в одном направлении, а дырки начнут двигаться в противоположном направлении.

13. Answer the following questions using the verbs: write, use, design, interest, experiment, read .

A	B
1. Can you name the recent inventions in electronics?	I’ve read a lot about that, but I haven’t remembered them yet.
2. Can you describe intrinsic conduction?
3. Do you know any information media?
4. The increase of temperature of germanium by one degree Centigrade increases its conductivity approximately by 5 per cent. Does the same take place in silicon?
5. Have you ever invented anything?
6. Is it easy for you to carry out laboratory tests in physics?
7. Are you an expert in programming?

14. Choose as many words from the table of ex.1 as you can and form sensible sentences.

For example: Both electrons and holes are charge carriers.

SPECIALIST READING

15. Read the text “The Movement of Holes”. Mark the following sentences as true (T) or false (F).

1. In figure 1 of exercise 2 we see that one covalent bond has broken, one electron has freed itself, and a hole has disappeared at point A.

2. The movement of electrons and holes is random.

3. A great number of electrons have freed themselves.

4. The hole has changed its position.

5. Conduction may take place in a pure semiconductor.

6. If some voltage is applied, the electrons begin to move in one direction and the holes begin to move in the opposite direction.

7. The increase of temperature of the semiconductor doesn’t increase its conductivity.

The Movement of Holes

If a silicon crystal is heated, the breaking of covalent bonds is taking place. Figures of exercise 2 in Unit 7 show what occurs in the atoms of the crystal. In one figure we see that one covalent bond has broken, one electron has freed itself, and a hole has appeared at point A. In the next figure we see that a second hole at point B has appeared. Now there are two free electrons. The second electron is passing the first hole. It has been attracted by the hole and there is no hole at point A. It seems that the hole has moved from position A to position B.

Then we see that the third electron has freed itself and recombination has taken place at some other point where the hole has disappeared.

The movement of electrons and holes is random.

But if some voltage is applied, then the electrons begin to move in one direction and the holes begin to move in the opposite direction. Thus, conduction may take place in a pure semiconductor. Such a conduction is known as intrinsic conduction. The increase of temperature of the semiconductor increases its conductivity.

16. Read the text again and complete the sentences with the correct ending.

1. If a silicon crystal is heated, …

2. As a result of breaking of one covalent bond, one electron …

3. The second electron is passing the first hole and it …

4. The third electron has freed itself and …

5. If some voltage is applied …

6. The conduction which takes place in a pure semiconductor is known as …

7. The increase of temperature of the semiconductor …

17. Work in pairs. Ask your partner some questions based on the text. Make sure you use the correct auxiliary verb.

For example:

The breaking of covalent bonds takes place (Where?)

Where does the breaking of covalent bonds take place?

1. In one figure we see that one covalent bond has broken (What …?) – …

2. If some voltage is applied, then the electrons begin to move (How?) – …

3. The increase of temperature changes the features of a semiconductor (How?) – …

4. Conduction may take place in (Where?) – …

SPEAKING

18. Summarize the text “The Movement of Holes” in 100 words using the figures of exercise 2:

Describe the process of recombination to your group mate using active terms of the Unit and the Present Perfect

Try to work as an interpreter. Translate the explanation of the way the electron frees itself given by your group mates from Russian into English.

21. Translate the text, which contains additional information about electron-hole movement with a dictionary in writing. Pay attention to the new words and the use of the Present Perfect.

Measuring the Movement of Holes in Crystal Surfaces

Vacancies in crystal surfaces are holes where atoms are missing from otherwise regular and uniform crystal lattices. Scientists have suspected for some time that vacancies are responsible for motion in crystals.

This motion occurs as the holes trade places with atoms, leading to atom-sized bubbles that percolate across crystal facets.

Now, researchers at the University of Leiden in the Netherlands have managed to measure vacancy motion in a copper crystal, and they have found that the holes are surprisingly mobile.

The discovery has important implications for the semiconductor industry and technologies that rely on tiny surface structures that may be gradually destroyed through vacancy mediated motion.

The researchers used a scanning tunneling microscope (STM) to study vacancy motion by monitoring the positions of indium atoms embedded in a copper lattice.

As vacancies move rapidly, changing places with atoms roughly a hundred million times each second at room temperature, comparatively slow STMs cannot image vacancies directly. Instead, the researchers calculated vacancy motion by tracking the positions of the indium atoms.

From one image to another, indium atoms exhibited long jumps which result from multiple vacancy interactions. Essentially, the indium atoms move across the copper crystal in much the same way that individual pieces may be maneuvered from one place to another in toys known as slide puzzles.

Although high vacancy mobility may be bad news for manufacturers of microstructures, the new insights will potentially help to optimize crystal growing procedures vital to the semiconductor industry.

In future work, the researchers plan to create vacancies artificially by selectively removing atoms from a chilled crystal surface. Provided that crystal is sufficiently cooled, the vacancies should move slowly enough to show up in STM images.

In Russian write a content-based summary of the text you have translated.

23. Make a reverse written translation (from Russian into English) of the text “Measuring the Movement of Holes in Crystal Surfaces”.

Find more information about the movement of holes and tell your groupmates.

UNIT VIII

SILICON

Language Work

Past Perfect Active (I had measured)

Affirmative

I/we/you/they	had	replaced/obtained/meant
he/she/it

For example:

· The engineers of our laboratory had already designed a highly effective device when this idea stroke the others.

· After radiophysicists had spent up to 80 per cent of their time on all kinds of analyses and tests they came to a certain conclusion.

Negative

I/we/you/they	hadn’t	replaced/obtained/meant
he/she/it

For example:

· The dean said the experiment hadn’t been carried out by five o’clock.

· The professor noted the scientists hadn’t employed this method by 2005.

Questions

Had	I/we/you/they	replaced/obtained/meant?
he/she/it

For example:

· Had pharmacists patented these new medicines when I began my career?

· Had robot assistants replaced people in their routine work by 2000?

Past Perfect Passive (it had been measured)

Affirmative

they	had	been	researched/fixed/recorded
it

For example:

· Mike carried out some experiments only yesterday, though other results had been obtained last year.

Negative

they	hadn’t	been	researched/fixed/recorded
it

For example:

· Professor said no new software products had been shown at the latest technical exhibition.

Questions

Had	they	been	researched/fixed/recorded?
it

For example:

· Had laptop computers been used in our country earlier than they appeared in Japan?

Fill in the table.

Noun	Verb	Adjective	Adverb	Translation	Transcription
	carry out			проводить (опыты)
compound				соединение
efficiency				коэффициент полезного действия	[I′fISqnsI]
feature				характерная черта
frequency				частота	[′frI:kwqnsI]
	manufacture				[‚mxnju′fxktSq]
means (c) / means of(fml)	mean
	press
oxide/ oxidation					[′oksaid] [‚oksI′deISqn]
surface					[′sq:fIs]

2. Open the brackets and put the verbs into the Past Perfect or Past Indefinite/Continuous Tense(Active or Passive).

1. In 1965, the Nobel Prize-winner in physics Charles K.Kao (receive) his PhD in the Imperial College in London but his pre-university education he (get) in Hong Kong.

2. The Einstein's theory of special relativity(introduce) first, and was later (consider) to be a special case of the more comprehensive theory of general relativity.

3. Galileo Galilei (establish) the principles which Newton later (use) to create a coherent theoretical framework for classical physics.

4. Niels Bohr (receive) a Nobel Prize for this work in 1922, just a year after Albert Einstein (receive) his.

5. Isaac Newton (be interested) in the discoveries of Galileo who earlier (prove) that the planets revolved around the sun, not the earth as people (think) at that time.

6. Isaac Newton's calculations (change) the way people (understand) the universe. Before it no one (be able) to explain why the planets (stay) in their orbits.

7. Less that 50 years before Isaac Newton (be born) it (think) that the planets (be held) in place by an invisible shield.

8. In the nineteenth century, the atom was thought to be a spherical blob of more-or-less uniform density but already two and a half millennia ago the concept of the atom (hypothesize) by the Greeks.

9. In 1963, Arno Penzias and Robert Wilson, two scientists in Holmdale, New Jersey, (work) on a satellite which (designe) to measure microwaves.

10. InAugust 1783 a French chemist Jacques Charles (invent) a different type of balloon that (use) hydrogen to get its lift, earlier, in November 1783, Pilatre de Rozier and Marquis d'Arlandes (make) the first manned flight in a Montgolfier balloon from the center of Paris to the city's suburbs.

11. Experimental physics (have) its debut with experimentation concerning statics, long before quantitative descriptions (become) popular among physicists and astronomers.

Make the sentences of ex.2 negative and interrogative.

4. For each situation, write a sentence ending with never … before. Use the verbs in brackets.

For example:

The student standing next to you in the laboratory was very nervous. It was his first experiment with this matter.

(experiment) He’d never experimented with this matter before.

1. Mike made a very thin insulation on a piece of silicon yesterday. He wasn’t very good at it because it was the first time he tried to control silicon oxidation. (control) He …

2. Last year we began to manufacture new electronic devices. It happened for the first time. (manufacture) We …

3. These electrolytes are usually used as insulators. Our researches ran into them only yesterday. (use) They…

4. Scientists patented their new device. (patent) Nobody …

Put the verb into the correct form, Past Perfect (I had measured) or Past Simple (I measured).

For example:

– Was Mike in the laboratory when you came?

– No, he (obtain) the results of the tests and (go) home.

1. I had a lot of energy when I started my work, so I … (begin, carry out) a new experiment.

2. The vacuum tube was full of mist when I got into the laboratory. Electrons … (form) a cloud around the cathode in a vacuum tube.

3. Sorry, but yesterday’s presentation of home appliances wasn’t too interesting for me, because I … (test) the electron device of the new generation a few months ago.

4. We were employing a new method when we … (see) something … (go) wrong, so we … (stop) to do it.

6. Complete these sentences with the following verbs (in the form of Past Perfect Passive): change, know, analyze, use, install.

1. Belarusian “Silicon Valley” was built after the international experience … in details.

2. Some parameters of the main machine … by a laboratory assistant before the professor came in.

3. There was a big storm last week and the city remained without electricity. Hundreds of patients didn’t die, because autonomous storage batteries … in the hospital.

4. We learnt about laser printers only a few years ago. Ink-jet printers … earlier.

5. The typewriter … to input data, before a computer was invented.

7. Rewrite these sentences into Past Perfect Passive/Active.

1. When at the master’s course all modern books were available for us, because electronic catalogs (create) earlier.

2. Before compact discs were designed diskettes (create).

3. We could easily buy energy efficient lamps in a special shop, because Edison (invent) a usual lamp.

4. We (eat) more natural food, before scientists created GMO.

5. Awesome interactive toys (develop) so we could present our children with them.

6. I (repaire) this equipment before you came.

7. After the new device (test) by the professor, it was installed in our laboratory.

Choose as many words from the table of ex.1 as you can and form sensible sentences. Use Past Perfect where possible.

For example: I must add that this material has one very important feature.

9. Form adjectives from the following verbs using the suffix -able and translate them:

measure, move, obtain, compare

For example: control – управлять; controllable – поддающийся управлению.

Translate the following international words without a dictionary paying attention to the suffixes.

Electromagnetic, optical, ionization, integration, plasma, atomic, relaxation, critical, equivalent (adj), experimentally, orientation, argument, molecule (n), configuration, information.

11. Read and translate word-combinations. Start from the first component.

1. electrolytic direct (непосредственный)oxidation indirect (непрямой)	3. prism quartz signalglass volcanic optical
2. contact emitting radiatingsurface reflecting working carrying	4. calcium cadmium chlorineoxide zink uranic nickel ferric

12. Match the following sentences with their translations.

1. Silicon is a very common element. 2. The addition of impurities is a very efficient way of causing conduction in any semiconductor. 3. Silicon oxidation can be controllable. 4. The term “impurity semiconductor” shows that some impurity is added to the semiconductor material. 5. The sand is mostly silicon oxide, i.e. the compound of silicon with oxygen. 6. In its pure form silicon is a dark, hard, rather glassy-looking material. 7. Elements either of group III or group V of the Periodic Table are used as impurities. 8. By means of controllable oxidation we can make a very thin insulation on a piece of silicon. 9. You have to understand first of all that extrinsic conductivity of semiconductors appears in addition to intrinsic conductivity. Secondly, by means of impurities we can change the number of positive charge carriers (holes) or negative charge carriers (electrons). This is the most important thing. 10. I mean indium [′indIqm], aluminium and gallium [′gxlIqm]. They are from group III. Elements of group V are arsenic [′a:snIk], antimony [′xntImqnI] and phosphorus[′fosfqrqs].

a. Посредством регулируемого окисления мы можем сделать очень тонкую изоляцию на куске кремния. b. Песок в основном представляет собой окись кремния, т.е. соединение кремния с кислородом. c. Термин «примесный полупроводник» показывает, что какая-то примесь добавлена к полупроводниковому веществу. d.Вы должен понять прежде всего, что примесная проводимость появляется в дополнение к собственной проводимости полупроводников. Во-вторых, при помощи примесей мы можем менять число носителей положительного заряда (дырок) или носителей отрицательного заряда (электронов). Это – самое важное. e. Элементы либо III, либо V группы Периодической таблицы используются как примеси. f. Кремний – очень распространённый элемент. g. Окисление кремния может быть управляемым. h. Добавление примесей – очень эффективный способ создания электропроводимости полупроводников. i. Я имею в виду индий, алюминий и галлий. Они из группы III. Элементами V группы являются мышьяк, сурьма и фосфор. j. В чистом виде кремний – это тёмный, твёрдый материал, несколько похожий на стекло.

SPECIALIST READING

13. Read the text “Silicon”. Find the answers to the following questions.

1. What’s silicon like in its pure form?

2. Is it a common element?

3. What is the structure of sand?

4. How can we make a very thin insulation?

5. What happens if an electric field is set up in the crystal of silicon?

6. What type of conduction do we call intrinsic?

7. Is silicon a conductor, a semiconductor or an impurity semiconductor? And what about the silicon oxide?

8. Can you name a very efficient way of causing extrinsic conductivity?

9. What elements are usually employed as impurities?

10. Name some impurities. Explain your choice.

Silicon

Silicon is a very common element. In its pure form silicon is a dark, hard, rather glassy-looking material. The sand, for example, is mostly silicon oxide, i. e. the sand is a compound of silicon and oxygen.

The silicon oxide is an insulator, and when it is necessary we can make a very thin insulation on a piece of silicon by means of controllable oxidation.

Silicon is a semiconductor. If an electric field is set up in the crystal of silicon, the electrons tend to move in the direction of the field and the holes tend to move in the opposite direction. Thus conduction of current in a pure silicon known as intrinsic conduction takes place. If a little impurity is added to silicon, it will become an impurity semi­conductor. The addition of impurities is a very efficient way of causing extrinsic conductivity. It appears in addition to intrinsic conductivity.

Elements of group III or group V of the Periodic Table are usually employed as impurities. These elements have either 3 or 5 valence electrons.

14. Read the text again and select the best completion for each sentence. Complete the following sentences using the multiple choice suggested. There might be more than one variant.

1. Silicon is …

a) an unknown element d) a very common element

b) a semiconductor e) an impurity semiconductor

c) a conductor

2. In its pure form silicon is …

a) light-coloured d) glassy-looking

b) hard e) dark

c) soft

3. We can make a very thin insulation on a piece of silicon by means of …

a) an electric field c) controllable oxidation

b) adding impurities d) placing it into another environment

4. Elements which are usually employed as impurities have either…

a) 3 or 5 valence electrons c) 3 or 6 valence electrons

b) 2 or 4 valence electrons d) 2 or 5 valence electrons

5. Elements of group III or group V of the Periodic Table are…

a) antimony e) copper

b) indium f) phosphorus

c) ferrum j) gallium

d) aluminium

15. Complete the sentences with the correct ending according to the text.

1. The sand is mostly …

2. The silicon oxide is …

3. If an electric field is set up in the crystal of silicon, the electrons tend to …

4. Conduction of current in a pure silicon is known as …

5. If a little impurity is added to silicon, it …

6. The addition of impurities is a very efficient way of …

7. Extrinsic conductivity appears in addition to …

8. Elements of group III or group V of the Periodic Table are usually …

9. These elements have …

10. They are …

SPEAKING

16. Summarize the text “Silicon” in 150 words.

17. Translate the text “Applications of Silicon” in writing paying attention to new technical terms.

Applications of Silicon

As the second most abundant element in the earth's crust, silicon is vital to the construction industry as a principal constituent of natural stone, glass, concrete and cement. The greatest impact of silicon on the modern world's economy and lifestyle has resulted from silicon wafers used as substrates in the manufacture of discrete electronic devices such as power transistors, and in the development of integrated circuits such as computer chips.

· Alloys

The largest application of metallurgical grade silicon, representing about 55% of the world consumption, is in the manufacture of aluminium-silicon alloys to produce cast parts, mainly for the automotive industry. Silicon is an important constituent of electrical steel, modifying its resistivity and ferromagnetic properties. Silicon is added to molten cast iron as ferrosilicon or silicocalcium alloys to improve its performance in casting thin sections, and to prevent the formation of cementite at the surface.

· Electronics

Pure silicon is used to produce ultra-pure silicon wafers used in the semiconductor industry, in electronics and in photovoltaic applications. Ultra-pure silicon can be doped with other elements to adjust its electrical response by controlling the number and charge (positive or negative) of current carriers. Such control is necessary for transistors, solar cells, integrated circuits, microprocessors, semiconductor detectors and other semiconductor devices which are used in electronics and other high-tech applications. In silicon photonics, it can be used as a continuous wave Raman laser medium to produce coherent light, though it is ineffective as a light source. Hydrogenated amorphous silicon is used in the production of low-cost, large-area electronics in applications such as LCDs, and of large-area, low-cost thin-film solar cells.

In Russian write a content-based summary of the text you have translated.

Make a reverse written translation (from Russian into English) of your summary.

Find more information about silicon applications and tell your group mates.

UNIT 9

SEMICONDUCTORS OF N-TYPE AND P-TYPE

Language Work

(I) If/when-clause (If/when I install …, it will result in …)

If/ when	+	Present Simple	+	Future Simple
I/we/you/they	add/form/leave	I/we/you/they he/she/it	will	except/attempt/ require
he/she/it	adds/forms/leaves

Or

Future Simple	+	if/ when	+	Present Simple
I/we/you/they he/she/it	will	except/attempt/ require	I/we/you/they	add/form/leave
he/she/it	adds/forms/leaves

For example:

If/when we add a small amount of arsenic to silicon, several valence electrons of each arsenic atom will form covalent bonds with the neighbouring atoms of silicon.

If/when gallium is introduced into a silicon crystal, each gallium atom will attempt to form a covalent bond with each of its four neighbouring silicon atoms.

Fill in the table.

Noun	Verb	Adjective	Adverb	Translation	Transcription
acceptor	accept	acceptor (impurity)	-	принимать, признавать, акцептор, акцепторная примесь	[qk′sept]
attempt				попытка	[q′tempt]
	calculate				[′kxlkjuleIt]
conclusion				заключение
	condense
		continuous		непрерывный	[kqn′tinjuqs]
	install			устанавливать	[in′stO:l]
			loosely	свободно
majority/ majority charge carriers				большинство/ основные носители заряда	[mq′GOrItI]
minority/minority charge carriers				меньшинство/ неосновные носители заряда	[maI′norItI]
	progress
	require			требовать

Put the verbs in brackets into the correct form.

1. What (occur) if holes and electrons (meet) in a semiconductor?

2. We (get) an N-type semiconductor, if we (add) arsenic to silicon.

3. If gallium (introduce) into a silicon crystal, it (result) into a P-type semiconductor.

4. If the electron (have no) pair, it easily (free) itself.

5. A semiconductor (call) an N-type semiconductor, if the holes (be) the minority charge carriers.

6. If the thermal agitation (apply) to the silicon crystal, we (have) the holes, moving in the same way as the holes introduced by atoms of gallium.

3. Write a sentence with if/when … for each situation.

For example:

We can’t pretend to the best mark on Electronics without the knowledge on P-type and N-type semiconductors.

If we have knowledge on P-type and N-type semiconductors we will pretend to the best mark.

1. I am not creating an impurity semiconductor, because I have no necessary equipment. If/when …, I….

2. I am not a member of the scientific group of the Semiconductor Development Department, so my name is not mentioned in the diploma. My name …, if/when I ….

3. I have always wanted to be a famous actor, and I’m not interested in conferences in physics.

If I …, my attention ….

4. My father works at the plant developing new types of semiconductor devices, and he is going to represent some of his equipment at a technical exhibition.

If my father …, he …

Answer the questions in the way shown.

For example:

Will you add some arsenic to silicon?

No. (deactivate thermal agitation). If I add some arsenic to silicon, I will deactivate thermal agitation.

1. Let’s start our discussion from P-type semiconductors.

I can’t agree. (not completely studied valence electrons). If we …

2. Could we help you to prepare for the conference?

No. (not be the only developer of the new aspects of P-type semiconductors usage). If you …

3. Are you ready to explain to us your new theory on different types of conductivity?

I hope so. (be the breakthrough in science). If I …

4. Why do you want to work in Silicon Valley? If I...

(improve semiconductor systems).

5. Will we discuss about the P-N junction?

Of course. (you understand the principles of a PNP transistor operation). If we …

Use your own ideas to complete the sentences.

For example:

If we apply thermal agitation to silicon, it will result in changing the conductivity of the specimen.

1. If an impurity atom has more valence electrons than the material, …

2. If holes are majority charge carriers in the material, …

3. If an semiconductor device has two P-N junctions, …

4. If an electron is attached to the nucleus very loosely, …

5. If you want to become the head of the Semiconductor Development Institute, …

6. Form verbs from the following words using the suffix – en and translate them: strength, broad, wide, tight, rough.

For example: hard – твёрдый, крепкий; harden – …

7. Translate the following international words without a dictionary. These words are often used in electronics.

Line (n), magnetic, parameter, mechanism, parallel (adj), method, procedure, normal (adj), technique (n), interval, typical, radiation, component, dielectric (adj), static.

Read and translate word-combinations starting from the first component.

electronic final gaseousstate neutral quantum	equivalent central horizontal state mechanical moving
resonance high extra-high frequency low radio superhigh	additional differential dynamicresistance negative pneumatic surface

Match the following sentences with their translations.

1. If we add a small amount of arsenic to silicon, several valence electrons of each arsenic atom will form covalent bonds with the neighboring atoms of silicon.	A. Рекомбинация происходит, когда дырки и электроны случайно встречаются в полупроводнике.
2. The atom of arsenic has five valence electrons. The fifth electron has no pair and is attached to the arsenic nucleus very loosely.	B. Каждый атом галлия из III группы вводит одну дырку в кристаллическую решётку кремния.
3. Each atom of arsenic will add one negative charge carrier to the silicon crystal. Such an impurity is called donor impurity. The resulting semiconductor will be called an N-type semiconductor.	C. Если мы добавим небольшое количество мышьяка в кремний, несколько валентных электронов каждого атома мышьяка создадут (образуют) ковалентные связи с соседними атомами кремния.
4.If the holes are in the minority in a semiconductor, we’ll call them minority charge carriers.	D. Тип примеси с галлием называется акцепторной примесью, и получающийся в результате полупроводник известен как полупроводник P-типа.
5. Recombination takes place when holes and electrons sometimes meet in the semiconductor.	E. Эта дырка может двигаться в кристалле таким же образом, как и дырка, полученная в результате теплового возбуждения.
6. Each atom of gallium from group III introduces one hole into the crystal lattice of silicon.	F. Если дырки составляют меньшинство в полупроводнике, мы будем называть их неосновными носителями заряда.
7. This hole is able to move about in the crystal in the same way as a hole produced by thermal agitation.	G. Атом мышьяка имеет пять валентных электронов. Пятый электрон не имеет пары и очень слабо связан с ядром атома мышьяка.
8. The type of impurity with gallium is called an acceptor impurity and the resulting semiconductor is known as a P-type semiconductor.	H. Каждый атом мышьяка добавит один отрицательно заряженный носитель в кристалл кремния. Такая примесь называется донорной примесью. Получившийся в результате полупроводник будет называться полупроводником N-типа.

Choose as many words from the table of ex. 1 as you can and form sensible sentences.

For example: Each gallium atom will attempt to form a covalent bond with each of its four neighboring silicon atoms.

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