CONCEPTS OF SEMI CONDUCTORS

Question 1

Are the materials which have a conductivity and resistivity in between conductors(generally metals) and non-conductors or insulators (such ceramics).

Answer 1

Semiconductors

Question 2

Their conductivity can be altered and controlled through

Answer 2

Doping and applying electrical fields

Question 3

What is Doping

Answer 3

Adding impurities

Question 4

Can conduct electricity under preferable conditions or circumstances

Answer 4

Semiconductors

Question 5

The charge carriers in semiconductors arise only because of external energy (thermal agitation).

Answer 5

True

Question 6

Semiconductor Conductivity

Answer 6

10^5 to 10^-6 mho/m

Question 6

Carriers accountable for the flow of current in semiconductors

Answer 6

Holes and electrons

Question 6

Holes (valence electrons) are the positively charged electric charge carrier whereas electrons are the negatively charged particles. Both electrons and holes are equal in magnitude but opposite in polarity

Answer 6

True

Question 6

Semiconductor resistivity

Answer 6

10^-5 to 10^-6 Ωm

Question 7

Acts like an insulator at Zero Kelvin

Answer 7

Semiconductor

Question 8

Semiconductor, on increasing temperature, it works as a

Answer 8

Conductor

Question 9

Semiconductors are smaller in size and possess less weight

Answer 9

True

Question 9

Their resistivity (semi conductor) is higher than conductors but lesser than insulators

Answer 9

True

Question 10

Most used semiconductors

Answer 10

Gallium arsenide, Silicon

Question 11

Is used in electronic circuit fabrication

Answer 11

Silicon

Question 12

Is used in solar cells, laser diodes, etc

Answer 12

Gallium Arsenide

Question 13

Materials that easily conduct electrical current

Answer 13

Semiconductors

Question 14

Materials that do not conduct electrical current under normal conditions like glass, ceramic, wood, and paper. They are used to prevent current when it is not wanted

Answer 14

Insulators

Question 15

Classifications of Semiconductors

Answer 15

Intrinsic, Extrinsic

Question 16

made to be very pure chemically. It is made up of only a single type of element

Answer 16

Intrinsic semiconductor

Question 17

Germanium (Ge) and Silicon (Si) are the most common type of intrinsic semiconductor elements

Answer 17

True

Question 18

They have four valence electrons (tetravalent). They are bound to the atom by covalent bond at absolute zero temperature

Answer 18

Intrinsic

Question 19

When the temperature rises, due to collisions, few electrons are unbounded and become free to move through the lattice, thus creating an absence in its original position (hole).

Answer 19

Intrinsic / true

Question 20

At absolute zero kelvin temperature, the covalent bonds are very strong and there are no free electrons, and the semiconductor behaves as a perfect insulator

Answer 20

True

Question 21

At above absolute temperature: the increase in temperature few valence electrons jump into the conduction band and hence it behaves like a poor conductor.

Answer 21

True

Question 22

The conductivity of semiconductors can be greatly improved by introducing a small number of suitable replacement atoms called IMPURITIES

Answer 22

True

Question 23

The process of adding impurity atoms to the pure semiconductor is called

Answer 23

Doping

Question 24

Pure semiconductor

Answer 24

Intrinsic semiconductor

Question 24

Density of electrons is equal to the density of holes

Answer 24

Intrinsic semiconductor

Question 25

Is a semiconductor in which impurities (pentavalent elements) are added to increase the number of free electrons, making electrons the majority carriers

Answer 25

n-type semiconductor

Question 26

What type of impurities are added to a pure semiconductor to form an n-type semiconductor

Answer 26

Pentavalent impurities

Question 27

In n-type semiconductor, what happens to the free electron when a group five element is added to silicon or germanium

Answer 27

Forms a covalent bond with four electrons of silicon or germanium, leaving one electron free as a mobile charge carrier

Question 28

Why is an n-type semiconductor called "n-type"

Answer 28

negative

Question 29

A semiconductor where trivalent impurities are added, creating holes as the majority carriers

Answer 29

p-type semiconductors

Question 30

What type of impurities are added to a pure semiconductor to form a p-type semiconductor

Answer 30

Trivalent Impurities

Question 31

Why is a p-type semiconductor called "p-type"

Answer 31

Positive

Question 32

In n-type semiconductors, electrons are the majority carriers, while in p-type semiconductors, holes are the majority carriers

Answer 32

True

Question 33

Which group of elements is used to dope silicon or germanium to create a p-type semiconductor

Answer 33

Boron, Gallium, or Indium

Question 34

What happens to the hole when a group three element is added to silicon or germanium

Answer 34

Forms covalent bonds with three electrons of silicon

Question 35

Boron, gallium, or indium are what type of impurities

Answer 35

Trivalent