Carrier transport and intersubband population inversion in coupled quantum wells

Abstract

We theoretically study the possibility of achieving intersubband population inversion in coupled GaAs quantum wells, taking into account the relevant physical mechanisms of resonant tunneling and intersubband emission-absorption processes. Two coupled quantum well structures having intersubband resonant wavelengths of 10 and 60 μm are considered. We find that, in the case of an operating wavelength of 60 μm, intersubband population inversion is achievable at acceptable injection current densities even for room-temperature operation. However, achievement of intersubband population inversion is significantly more difficult at the shorter wavelength. The temperature and carrier transit time dependence of intersubband population inversion are also calculated.