given the electron effective mass for the GaAs is $0\mathrm{.}067$me$,$ calculate the thermal velocity of the electrons in the CB of a non degenately doped GaAs at room temp of $300$k$.$If the drift mobility of the electrons the mean free time between electron scattering events $($between electrons and lattice vibrations$)$ and if drift mobility$=$ e$*$mean free time$/$me$,$ calculate mean free time, given drift mobility$=8500$ cm$^2$V$^-1$s$^-1.$ Calculate the drift velocity vd$=$drift mobility $($E$)$ of the CB electrons in an applied field E of $10^5$ V m$^-1.$ what is your conclsuion