Calculate the approximate donor binding energy
Calculate the approximate donor binding energy for Si (r = 11.7,m^{x}_{n}= 1.18 m_{0})
Solution: From E= m^{*}_{n}q^{4} / 2(4 πε_{0}ε_{r})^{2} [h/(2 π)]^{2} we have
= 1.867 x 10^{-20} J = 0.117 eV.
Note: The effective mass used here is an average of the effective mass in different crystallographic directions, and is termed as the "conductivity effective mass" with values of 1.28 m_{0} (at 600 K), 1.18 m_{0} (at 300 K), 1.08 m_{0} (at 77 K), and 1.026 m_{0} (at 4.2 K).