Temperature-induced carrier redistribution among nonidentical multiple quantum wells

Summary form only given. Nonidentical multiple quantum wells (MQWs) have been widely used for broadening gain bandwidth of semiconductor lasers and amplifiers. However, carrier distribution among those MQWs is not uniform and thus complicates actual gain profiles. In this work, we further explore the dependence of carrier distribution on temperature and discover that temperature characteristics of semiconductor lasers with nonidentical MQWs are very different from conventional ones with identical MQWs. The origin is due to the strongly temperature-dependent Fermi-Dirac distribution, which favors carriers in high-energy states at large temperature. As a result, carriers redistribute among those QWs as temperature varies. For laser diodes with nonidentical MQWs, the temperature-induced carrier redistribution could make the lasing wavelength much less dependent on temperature, compared to the bandgap shrinkage. Theoretical reasons and experimental evidence are given.