Free Carrier Absorption in n-GaAs

概要

論文の詳細を見る
The infrared absorption between 400 and 4,000 cm^<-1> is measured as a function of carrier concentration for n-type GaAs at three different temperatures of 90゜, 300゜ and 450K. The absorption in the 800 to 2,000 cm^<-1> region is only due to the optical transition of free carriers. The free carrier absorptions arising from three scattering sources, i.e. acoustic and optical phonons, and ionized impurities, are numerically evaluated in the infrared region. At a constant wave number, 1,000 cm^<-1>, a comparison of the theoretical cross section with the experimental value is performed and the degree of compensation of impurities (N_<imp>/N_e) for each sample is graphically determined using the total photon capture cross section vs. carrier concentration chart. The numerical results of the wave number and temperature dependences of free carrier absorption are in good agreement with the experimental data in the wide range of carrier concentrations from 1×10^<16> to 1×10^<18> cm^<-3>. A relatively sharp peak is detected at ν^^-=3,200 cm^<-1> at 90K. The absorption is suggested to occur by a transition from a deep impurity level (0.4 eV) to the conduction band.
社団法人応用物理学会の論文
1972-03-05