Question

4) Gallium arsenide (GaAs) is a semiconductor material of great interest for its high power-handling capabilities and fast response time. (a) Calculate the drift speed of electrons in GaAs for a field of 10 V/cm if the electron mobility is un = 8500 cm2/Vs. (b) What percent of the electron's thermal speed at 300 K is this drift speed? (c) Assuming an effective electron mass equal to the free electron mass, calculate the average time between electron collisions. (d) Calculate the electronic mean free path.

Answer 1

Given that E lectote fteld E 10 v/em 1000 V /m Electron moblWer μη-8500 cm/Vs Temperature T 300K e te lattory between datft speed &u mobilitr i ラ吃 = 8500 x 10 cm/s = 85000 cm/s b Themal eneay ol election x 1.38 x 1o23 300 hy 9 Ix10 31 T168 x07277 x10 c> 'The avea°1e time between electron count on 。요 9dE , tis the av coltgion time -12 2E 16 x101x 1000 ラ℃=4.83 ps dy Mean free path of electrons ts ご1.168 x 105 x 4.83x10-12

Answer 2

VdM RE 8500 x 10850 m/s 6 Vth = 3KBT 3X:38x10-23X300 9.10X10 31 m = 1.168x109 m/s PA YAN 850 1168 X10 -3 - 7.277x10 5 0.7217 9.1x10-31 X 850 4.83x10-12 IS 0001X61 01X94 -12 LV th x T - 1.168 x 105 x 4.83x10 10.5641 um