Theoretical modeling for quantum-confined Stark effect due to internal piezoelectric fields in GaInN strained quantum wells

Recent experimental investigations revealed that the biaxial stress in thin InGaN layers grown on thick GaN layer induces a large piezoelectric field along [0001] orientation that causes red-shift in optical transitions and reduction in oscillator strengths because of spatial separation of the electron and hole wave functions. In this Letter based on theoretical modeling we determined the well width z-dependent effect on red-shifted quantum-confined Stark effect (QCSE) in GaN/InxGa1-xN (x=0.13) strained quantum well structures. Analyses are based on the solution of Schroedinger equation in a finite well including the internal piezoelectric electric field (F) due to the strained polarization as the perturbation potential. Our theoretical results show: (1) the red-shift in optical transition has a quadratic well-width form as it is for infinite wells (Davies, 1998) , (2) assuming the model based on a carrier effective mass dependence on the width of quantum wells, m*(z), fits the experimental data (Takeuchi et al., 1997) much more accurate compare to the model with constant effective mass, m*.