Effects of well thickness on the light emission in InGaN/GaN and GaN/AlGaN multiple quantum wells

Picosecond time-resolved photoluminescence (TRPL) has been employed to study the effects of well thickness on the light emission properties and recombination dynamics in In/sub x/Ga/sub 1-x/N/GaN and GaN/Al/sub x/Ga/sub 1-x/N multiple quantum wells (MQWs) grown both by metal-organic chemical vapor deposition (MOCVD) and reactive molecular beam epitaxy (MBE). In this work we present results from a set of MOCVD grown In/sub x/Ga/sub 1-x/N/GaN and a set of MBE grown GaN/Al/sub x/Ga/sub 1-x/N MQW samples with well thicknesses varying from 20 to 90 /spl Aring/. Results from these MQW samples are compared with each other and also to InGaN and GaN epilayers to extrapolate the mechanisms and quantum efficiency of the optical emission in these structures. The implications of these results on device applications, in particular for blue LEDs and laser diodes will be discussed.