Optical measurements of stress distributions in GaAs at low temperature

We have measured the stress distribution at He temperature on two epitaxial GaAs wafers which were compressed along one edge. The stress was determined non-destructively at different points on the wafer surface by using the line-splitting and the lineshifts of the photoluminescence spectra of the acceptor-bound excitons in comparison with calibration spectra at known uniaxial stress.