Optical properties of III-nitride laser diodes with wide InGaN quantum wells

In this paper we show that, despite a high piezoelectric field, a wide InGaN quantum well (QW) can be more effective as the active region of laser diodes (LDs) than the thin ones usually used. The optical gain in the LDs with a single wide QW is studied. It is shown that the differential gain in a LD with 10.4 nm QW is higher than in a LD with three 2.6 nm thick QWs. The high optical gain in a wide QW is interpreted as originating from transitions through excited states. Additionally, a substantial difference in lasing spectra between LDs with wide and thin QWs is found.