Chapter 8-1

熱敏電阻器

Ge Si

ħ << Eg

ħ = Eg - ħ

Crystal momentum kc

electron crystal momentum kC , phonon momentum K creation of phonon

absorption of phonon

(T = 0)

Direct Transition Indirect Transition

kc = 0

ħ << Eg

ħ = Eg - ħ

Crystal momentum kc

electron crystal momentum kC , phonon momentum K creation of phonon

absorption of phonon

Optical absorption to determine the (direct) energy gap of InSb

Direct Transition at 0.23V

OF AN ELECTRON IN AN ENERGY BAND

(1)

(2)

(3)

Ch. 8,

Eq. 43, 49

B

B

KE

(1) Without interaction with the crystal potential

(2) With interaction with the crystal potential

Free electrons

Then, we sum over all possible G

for a given G,