Advertisements
Advertisements
Question
Electric conduction in a semiconductor takes place due to
Options
electrons only
holes only
both electrons and holes
neither electrons nor holes.
Advertisements
Solution
both electrons and holes
A hole is created in a semiconductor when a valence electron moves to the conduction band. When potential difference is applied across the semiconductor, the electron drifts opposite to the electric field applied, while the hole moves along the electric field. Therefore, electric conduction takes place in a semiconductor because of both electrons and holes.
APPEARS IN
RELATED QUESTIONS
Distinguish between a metal and an insulator on the basis of energy band diagrams ?
The conduction band of a solid is partially filled at 0 K. Will it be a conductor, a semiconductor or an insulator?
What is the resistance of an intrinsic semiconductor at 0 K?
We have valence electrons and conduction electrons in a semiconductor. Do we also have 'valence holes' and 'conduction holes'?
Let np and ne be the number of holes and conduction electrons in an intrinsic semiconductor.
In a transistor,
The impurity atoms with which pure silicon may be doped to make it a p-type semiconductor are those of
(a) phosphorus
(b) boron
(c) antimony
(d) aluminium.
Indium antimonide has a band gap of 0.23 eV between the valence and the conduction band. Find the temperature at which kT equals the band gap.
Estimate the proportion of boron impurity which will increase the conductivity of a pure silicon sample by a factor of 100. Assume that each boron atom creates a hole and the concentration of holes in pure silicon at the same temperature is 7 × 1015 holes per cubic metre. Density of silicon 5 × 1028 atoms per cubic metre.
The product of the hole concentration and the conduction electron concentration turns out to be independent of the amount of any impurity doped. The concentration of conduction electrons in germanium is 6 × 1019 per cubic metref conduction electrons increases to 2 × 1023 per cubic metre. Find the concentration of the holes in the doped germanium.. When some phosphorus impurity is doped into a germanium sample, the concentration o
What is forbidden band?
If the lattice constant of this semiconductor is decreased, then which of the following is correct?
An n-type semiconductor is
For germanium crystal, the forbidden gas energy gap
In a common-base circuit calculate the change in the base current if that in the emitter current is αmA and a = 0.98
In a common base configuration Ie = 1 mA α = 0.95 the value of base current is
The energy required by an electron to jump the forbidden band in silicon at room temperature is about ______.
With reference to semiconductor physics, answer the following question.
What is meant by “Forbidden band" of energy levels?
