Carbon, silicon and germanium have four valence electrons each. These are characterised by valence and conduction bands separated by energy band gap respectively equal to (Eg)C, - Physics | Shaalaa.com

Band StructureThe diagram shows the valence band, conduction b... | Filo

(i) Assuming that the conduction and valence bands have isotropic but different effective masses, and no valley degeneracy, determine the T-dependent coefficients in front of the exponentials which we omitted form Eqs. (9.4) and (9.5) in the limit T →0, and show that Eq. (9.6) is valid despite the difference between conduction and valence bands. (ii) Generalize (i) to the case of anisotropic effective mass and to multi-valley cases (including the possibility that the valley degeneracy may be dif