Landau level electron scattering and lifetimes in n-GaAs and n-InP

Far-infrared laser saturation spectroscopy has been used to determine the dependence of the cyclotron resonance absorption linewidth (and hence the carrier momentum scattering time) on carrier density in n-type GaAs, showing this to have an n1/2 dependence. The authors also report the first observation of saturation of the cyclotron resonance absorption in n-InP and fit this on a three-level model. The N=1 Landau level lifetime tau 1 has thus been determined to be 0.9 ns, in good agreement with the lifetime obtained from emission studies.