Question

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The Figure below shows the schematic band diagram of an indirect semiconductor. Holes in the valence band tend towards the energy maximum of the valence band whereas electrons in the conduction band tend towards the conduction band minimum. For the following calculations use the values of silicon: Indirect band-gap energy WG = 1.13eV and lattice constant a = 0.543 nm.

(a) Calculatethefrequencyofaphotonthatcorresponds
to the band gap energy of silicon. How large is the momentum of this photon? Compare this momentum to the crystal momentum of the electron.

(b) Consider now a phonon with a momentum that corresponds to the crystal momentum of the electron. Compare the energy of the phonon to the band gap energy when you consider a value of vs = 8433 m/s for the speed of sound in silicon.

(c) Is it possible to build an efficient light source using silicon? Rationalize your answer

Answer 1

Answer:-

given that

a) The expression bar band gap energy of semiconductor

frequency of photos corresponding the band gap is

momentum of the photon is

Crystal momentum of the research is

b) energy of photon to thee bandgap is

c) No because silicon needs three particles ...

light emission electronics relaxing variance band need photon momentum and energy conservation.

Crystal momentum of the research is

b) energy of photon to thee bandgap is

c) No because silicon needs three particles ...

light emission electronics relaxing variance band need photon momentum and energy conservation.