Photoluminescence and energy dispersive X-ray measurements on residual strain in bulk InxGa1-xAs crystal

Photoluminescence (PL) and energy dispersive X-ray (EDX) experiments have been performed to measure both residual strain and composition in bulk In_xGa_1-xAs mixed crystal grown by the normal freezing technique. It is found from the comparison between the PL and EDX results that there exists a large amount of residual strain due to the compositional variation in the crystal. In order to evaluate the amount of residual strain, a simple one-dimensional strain model has been proposed. Using the model, the strain profiles estimated independently from the EDX and PL data are in agreement. Moreover, the compositional profile measured by EDX fairly agrees with that obtained after excluding the strain from the PL data.