The effect of interdiffusion on the intersubband optical properties in a modulation-doped quantum-well structure

The linear and nonlinear (based on optical field intensity) intersubband absorptions in conduction band, and its change in refractive index in AlGaAs-GaAs interdiffused quantum wells (QWs) are presented. The calculation of the electron energy levels and the envelope wave functions in a modulation doped interdiffused QWs with screening effects are considered. QW interdiffusion shows a wavelength tunability of the intersubband absorption peaks and refractive index dispersions. This shifting of the transition energies is also demonstrated here to be a useful technique for broad-band and multicolor photodetector application. In addition, it can serve to remove noise, such as minor peaks and dispersions, in the optical spectra.