Advertisements
Advertisements
प्रश्न
Sn, C, and Si, Ge are all group XIV elements. Yet, Sn is a conductor, C is an insulator while Si and Ge are semiconductors. Why?
Advertisements
उत्तर
The conduction level of any element depends on the energy gap between its conduction band and valence band.
In conductors, there is no energy gap between the conduction band and valence band. For insulators, the energy gap is large and for semiconductors the energy gap is moderate.
The energy gap for Sn is 0 eV, for C is 5.4 eV, for Si is 1.1 eV and for Ge is 0.7 eV related to their atomic size.
Therefore Sn is a conductor, C is an insulator, and Ge and Si are semiconductors.
APPEARS IN
संबंधित प्रश्न
Distinguish between 'intrinsic' and 'extrinsic' semiconductors
Distinguish between intrinsic and extrinsic semiconductor. (Give any two points).
In a p-type semiconductor, the acceptor impurity produces an energy level ______
When p-n junction diode is forward biased, then ______.
In p-type semiconductor, the dopant is ______.
The electron and hole concentration in a semiconductor in thermal equilibrium is given by ______.
State how a p-type semiconductor will be obtained from a pure crystal of a semiconductor.
Distinguish between n-type and p-type semiconductors.
Why are elemental dopants for Silicon or Germanium usually chosen from group XIII or group XV?
Two crystals C1 and C2, made of pure silicon, are doped with arsenic and aluminium respectively.
Identify the extrinsic semiconductors so formed.
Name the extrinsic semiconductors formed when pure germanium is doped with a Pentavalent impurity. Draw the energy band diagram of extrinsic semiconductors so formed.
- Statement I: By doping silicon semiconductor with pentavalent material, the electrons density increases.
- Statement II: The n-type semiconductor has net negative charge. In the light of the above statements, choose the most appropriate answer from the options given below:
Pieces of copper and of silicon are initially at room temperature. Both are heated to temperature T. The conductivity of ______.
- Assertion (A): Putting the p-type semiconductor slab directly in physical contact with the n-type semiconductor slab cannot form the pn junction.
- Reason (R): The roughness at contact will be much more than inter atomic crystal spacing and continuous flow of charge carriers is not possible.
With an increase in the temperature, the electrical conductivity of a semiconductor ______.
What type of semiconductor is obtained when a crystal of silicon is doped with a trivalent element?
