Line-Broadening of Cyclotron Resonance due to Lattice and Neutral Impurity Scattering in Silicon and Germanium

Abstract

The relaxation times for electrons in germanium and silicon were measured from the half-width of the cyclotron resonance line at 6 mm wavelength over the temperature range from 1.6° to 20°K for the specimens of different impurity concentration. Above 3°K the reciprocal relaxation times for electrons in high purity specimens are 1/τ 0 =3.6×10 8 T 3/2 sec -1 for germanium and 1/τ 0 =2.6×10 8 T 3/2 sec -1 for silicon, respecitively. These results show that the acoustical lattice scattering is predominant in this region. For impure specimens, deviation from the T 3/2 -dependence was observed at low temperatures. This deviation is due to neutral impurity scattering. The applicability of Erginsoy's formula for neutral impurity scattering was examined. It was found that the conventional Erginsoy,s formula corrected for chemical shift agrees fairly well with the experimental results.