Advertisements
Advertisements
Question
Distinguish between a conductor, a semiconductor and an insulator on the basis of energy band diagrams.
Advertisements
Solution
The energy-band diagram of a conductor is represented as
The energy-band diagram of a semiconductor is represented as
The energy-band diagram of an insulator is represented as
APPEARS IN
RELATED QUESTIONS
The electrical conductivity of pure germanium can be increased by
(a) increasing the temperature
(b) doping acceptor impurities
(c) doping donor impurities
(d) irradiating ultraviolet light on it.
A semiconductor is doped with a donor impurity.
Find the maximum wavelength of electromagnetic radiation which can create a hole-electron pair in germanium. The band gap in germanium is 0.65 eV.
(Use Planck constant h = 4.14 × 10-15 eV-s, Boltzmann constant k = 8·62 × 10-5 eV/K.)
Let ΔE denote the energy gap between the valence band and the conduction band. The population of conduction electrons (and of the holes) is roughly proportional to e−ΔE/2kT. Find the ratio of the concentration of conduction electrons in diamond to the in silicon at room temperature 300 K. ΔE for silicon is 1.1 eV and for diamond is 6.1 eV. How many conduction electrons are likely to be in one cubic metre of diamond?
What is forbidden band?
A window air conditioner is placed on a table inside a well-insulated apartment, plugged in and turned on. What happens to the average temperature of the apartment?
Two radioactive substances A and B have decay constants 3λ and λ respectively. At t = 0 they have the same number of nuclei. The ratio of the number of nuclei of A to those of B will be `1/"e"` after a time interval:
If the lattice constant of this semiconductor is decreased, then which of the following is correct?
- Assertion (A): In insulators, the forbidden gap is very large.
- Reason (R): The valence electrons in an atom of an insulator are very tightly bound to the nucleus.
With reference to semiconductor physics, answer the following question.
In which material “Forbidden band” is absent?
