Arrange the following semiconductor materials on the basis of Energy - Bandgap (E_{g}) from highest to lowest
A) ZnSe
B) InAs
C) CdTe
D) Ge
E) InP
Choose the correct answer from the options given below:
Energy Gap: In solid-state physics, an energy gap is an energy range in a solid where no electron exists. i.e. an energy range where the density of states vanishes.
Band-Gap: If an energy gap exists in the band structure of a material, it is called a bandgap. The physical properties of a semiconductor are to be determined by bandgap.
Energy gap fro some material:
E_{g} → 0.785 ev (Ge), 1.21 ev (Si)
E_{g} (300 K)→ 0.72 ev (Ge) 1.1 ev (Si)
E_{g} (300 K) → 1.47 ev (GaAs)
Explanation:
Materials |
Energy gap (eV) @ 300 K |
Si |
1.11 eV |
Ge |
0.7 eV |
Zn Se |
2.7 eV |
In As |
0.36 eV |
Cd Te |
1.49 eV |
In P |
1.35 eV |
Thus correct order is:
Zn Se > Cd Te > In P > Ge > In As
Option (4) correct.
Extra point:
Variation of energy gap with temperature:
i.e. E_{g} = E_{go} – β_{0}T ev
E_{go} → energy gap at 0K, β_{0} → material constant.
E_{g} → energy gap at temp. (T K)
Thus when temperature increases, the material bandgap decreases.