Question

1. The carrier effective masses in a semiconductor are m = 0.621m, and m* = 1.4m, Determine the position of the intrinsic Fermi level with respect to the center of the bandgap at T = 300 K.

Answer 1

In order to determine the position of Intrinsic Fermi level

$E_{Fi}$ is the intrinsic fermi level

$E_{midgap}$ is the mid or centre energy level

T=300k

where k is the Boltzman constant

$E_{Fi}-E_{midgap}=\frac{3}{4}*kT*ln(\frac{m_{p}^{*}}{m_{n}^{*}})$

is the effective carrier mass in the semiconductor

шриш П

$\therefore E_{Fi}-E_{midgap}=\frac{3}{4}*(0.0259)ln(\frac{1.4m_{o}}{0.621m_{o}})=15.82meV$

Hence intrinsic fermi level lies in 15.82meV above the centre of bandgap at T=300k