Temperature dependence of residual stress in epitaxial GaAs/Si(100) films determined from photoreflectance spectroscopy data

In the temperature range T = 10-300 K, photoreflectance spectroscopy was us ed to study the temperature dependence of residual stress in epitaxial n-Ga As films (1-5 mu m thick, electron concentration of 10(16)-10(17) cm(-3)) g rown on Si(100) substrates. A qualitative analysis showed that the photoref lectance spectra measured in the energy region of the E-0 transition in GaA s had two components. They consisted of the electromodulation component cau sed by the valence subband \3/2; +/-1/2]-conduction band transition and the low-energy excitonic component. The magnitude of stress was determined fro m the value of the strain-induced energy shift of the fundamental transitio n from the subband \3/2; +/-1/2] with respect to the band gap of the unstre ssed material E-0(T)-E-0(\3/2; +/-1/2])(T). The increase in the energy shif t E-0-E-0(\3/2; +/-1/2]) from 22 +/- 3 meV at 296 K to 29 +/- 3 meV at 10 K , which was found in the experiments, gives evidence of an increase in biax ial stress with decreasing temperature. (C) 2000 MAIK "Nauka/Interperiodica ".