Theoretical analysis of intersubband optical absorption in asymmetric AlInN/GaN/AlInN quantum well heterostructures

Abstract

The intersubband optical absorption coefficients were theoretically investigated in asymmetric AlInN/GaN/AlInN quantum wells. The electron band parameters are calculated by solving, self-consistently, the one-dimensional Poisson and Schrödinger equations under Hartree and effective mass approximations. The intersubband optical absorption between the two lowest levels was calculated based on the density matrix formalism. The effects of polarization, indium composition and delta-doping on the optical absorption coefficients in AlInN/GaN double heterostructures were studied. Results have revealed: i) an enhancement of the total (linear plus nonlinear) absorption coefficient peak and a reduction of wavelength due to the polarization effects ii) that the peak of the total optical absorption coefficient increased and showed a red shift upon increasing indium composition iii) that the peak of the total absorption coefficient increased and red-shifted or blue-shifted through optimizing the concentration of the planar doping in the AlInN barriers. Furthermore, the use of a back doping with a delta-shaped profile was identified as a consistent approach to carry out the transition 1.55 µm. The results in this study could be useful for the design and applications of optoelectronic devices operating at 1.55 µm.