Many-body effects in GaN/AlGaN quantum well with the spin-orbit interaction

摘要

Summary form only given. Semiconductor lasers based on III-V nitrides such as GaN or InGaN are of considerable interest for application in blue-green and near-ultraviolet emitters. There has been considerable progress at a laboratory level since 1990. In recent years, there have been many calculations of optical gain in bulk nitride materials and in quantum well structures, and usually these have relied on valence and conduction band structures derived using effective-mass k.p theory. However in wurtzite GaN the heavy-hole (HH), light-hole (LH), and crystal-field split-orbit valence bands are very close to each other such that the holes are distributed among them, thereby influencing the stimulated emission rate at a given total carrier density. In the report, we focus attention on the spin-orbit interaction which is usually neglected in literature. The spin-orbit interaction removes double degeneracy of the HH, LH and CH bands. Some band structure calculations using the empirical pseudopotential method, or the empirical tight-binding method, have shown that the splitting is up to 10 meV near the /spl Gamma/-point which is comparable with the thermal energy at room temperature and similar to the energy separation of the split-off band in GaN. Including the spin-orbit interaction therefore has a strong influence on the predicted optical characteristics. We present our optical gain calculation result in a wurtzite GaN/Al/sub 0.2/Ga/sub 0.8/N quantum well of width of 50 /spl Aring/.