Saturation of Impurity Cyclotron Resonance and Effect of 337 µm Radiation on Carrier Numbers and Mobilities in n-InSb

Abstract

Effect of intense far-infrared radiation on magneto-absorption, photoconduction and photo-Hall effect on n -InSb containing 2.5×10 13 cm -3 electrons were investigated at liquid helium temperatures by using an HCN laser. Saturation of impurity cyclotron resonance (ICR) and enhancement of conduction-electron cyclotron resonance (CCR) with the radiation intensity were found. This can be explained by the effect of relaxation processes where the electrons excited to impurity state (010) drop to Landau state N =0 and accumulate there. The relaxation time for the ICR saturation was obtained as 7×10 -9 sec at 1.7 K. The photoconductivity and the photo-Hall effect were analysed on the basis of the two-band conduction model. The result demonstrates that with an increase of the radiation intensity the number of conduction electrons increases consistently with the proposed relaxation processes, and in addition the impurity-band mobility also increases.