The influence of residual strain on Raman scattering in InxGa1−xAs single crystals

Micro-Raman scattering studies were performed on bulk InxGa1−xAs single crystal grown by the two-step multi-component zone melting method, with the aim to understand the influence of residual strain on the shifts in phonon frequencies in Raman spectra. It is observed that the LOGaAs phonon frequency is varied for various measurement points, which may be related to the compositional variation in the samples. However, it is found from precise micro-Raman measurements both in a corner region and in a chipped region that there exists a large amount of residual strain in the samples. By comparing the observed LOGaAs phonon frequencies with those estimated from the compositions determined by the energy dispersive X-ray analysis, they are found to be shifted by about 9.5 cm−1 due to residual strain, which corresponds to a strain value of the order of 10−2.