Numerical design of AlGaN/GaN double quantum wells for intersubband absorption in the wavelength range of λ 9.3-10.6 μm

The wurtzite AlGaN/GaN double quantum wells (DQWs) are designed and studied by numerical simulation based on ensemble Monte Carlo method. Structural parameters are carefully chosen for three-level and four-level DQWs to optimize intersubband absorption shapes in the wavelength range 9.3-10.6 μm. It is shown that three-level AlGaN/GaN DQWs have some advantages over four-level DQWs in structural design for optically pumped terahertz lasers. The requirements for resonant optical pumping and resonant LO-phonon scattering in terahertz lasers restrict the wide quantum well of four-level DQWs in quite narrower width range than the three-level DQWs. The results of this work should provide useful guidance for the design of optically pumped quantum well lasers.