ABSTRACT
InGaN-based blue light-emitting diodes (LEDs) play an essential role in high-e¶ciency, solid-state white light sources. To improve the e¶ciency of LEDs, photoluminescence (PL) measurements have been used extensively to understand internal material properties and to reveal the unique nature of nitride alloys, in particular, InGaN. Excellent review books and papers on basic nitride materials covering the exciting progress of the last two decades are now available (see, for example, Refs. [1,2]). In this chapter, we introduce key phenomena that govern optical device performance through PL measurement data together with typical examples of LEDs and laser diodes (LDs). –ese PL data are not necessarily typical, but rather are ones that may give insight about nitride alloy systems. Recent £ndings regarding nonpolar and semipolar GaN technology used to suppress the quantum con£ned stark e¢ect (QCSE) are also covered.
