Effects of crystal orientation on the optical gain characteristics of blue AlInGaN/InGaN quantum-well structures

The effects of crystal orientation on the optical gain characteristics of blue AlInGaN/InGaN quantum-well (QW) structures with a reduced internal field were investigated by using the non-Markovian model with many-body effects. The AlInGaN/InGaN system has a larger matrix element than the conventional InGaN/GaN system because the former has a smaller internal field than the latter for relatively small crystal angles. As a result, for QW structures with a relatively small crystal angle (θ = 30°), the AlInGaN/InGaN system is shown to have a much larger optical gain than the conventional InGaN/GaN system. On the other hand, in the case of QW structures with a large crystal angle (θ = 90°), the AlInGaN/InGaN system is shown to have a smaller optical gain than the conventional InGaN/GaN system. Hence, we expect that we can obtain high-efficiency optoelectronic devices by using quaternary AlInGaN QW for relatively small crystal angles.