The energy of a photon of sodium light `(lambda=589 nm)`equal the band gap of a semiconducting material.(a)Find the minimum energy E requried to create a hole-electron pair.(b)Find the value of `E//kT`at a temperature of 300K.

Explanation

(a) `E=(hc)/(e lamda)("in eV")` so `E = (12400)/(lamda) ("E is in eV and" lamda "is in A")lamda = 5890 Å`
so `E=(12400)/(5890)=2.1eV`
(b) `(E)/(kT)=(2.1xx1.6xx10^(-19)J)/(1.38xx10^(23)xx300)=81`.