Advertisements
Advertisements
प्रश्न
Explain why does conductivity of germanium crystals increase on doping with galium.
उत्तर
- When Ge is doped with group 13 elements, for example, gallium, the structure of crystal lattice does not change.
- 3 valence electrons of gallium are used up in the normal covalent bond.
- For one dopant atom, one hole is created because the place where fourth electron is missing is called vacancy or hole and is responsible for conduction of germanium doped with gallium.
Electron from neighbouring atom comes and fills the hole, thereby creating a hole in its original position. Under the influence of electric field electrons move towards positively charged plates through these and conduct electricity. The holes appear to move towards negatively charged plates.
APPEARS IN
संबंधित प्रश्न
p - type semi-conductors are made by mixing silicon with impurities of-
- germanium
- boron
- arsenic
- antimony
In a semiconductor, acceptor impurity is.................................
- antimony
- indium
- phosphorous
- arsenic
Give reasons : Silicon on doping with Phosphorous forms n-type semiconductor.
A pure semiconductor is ________.
(a) an extrinsic semiconductor
(b) an intrinsic semiconductor
(c) p-type semiconductor
(d) n-type semiconductor
What is the ratio of octahedral holes to the number of anions in hexagonal closed packed structure?
To get n-type of semiconductor, germanium should be doped with ____________.
p-type semiconductors are formed when Si or Ge are doped with ____________.
Which of the following oxides behaves as conductor or insulator depending upon temperature?
To get a n-type semiconductor from silicon, it should be doped with a substance with valence ______.
How does the doping increase the conductivity of semiconductors?
