Intersubband population inversion in coupled quantum well structure

The authors present a dynamical model for carrier transport and 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 μm and 60 μm are considered. It is found 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