The mechanism of blueshift in excitation-intensity-dependent photo luminescence spectrum of nitride multiple quantum wells

(1 1 (2) over bar 0) GaN/InGaN multiple quantum wells (MQWs) were grown on (1 (2) over bar 0 2) sapphire by metal-organic vapor phase epitaxy. The excitation-intensity-dependent photoluminescence (PL) spectrum of these samples was measured, and no peak shift was observed. This phenomenon was attributed to the absence of piezoelectric field (PEF) along the growth orientation of the (1 1 (2) over bar 0) face MQWs. Our experimental results showed that PEF was the main reason causing peak blueshift in excitation-intensity-dependent PL spectrum of (0 0 0 1) InGaN/GaN NIQWs. It was expected that fabricating (1 1 (2) over bar 0) face nitride device should be a method to avoid PEF and get low-threshold, high-quantum-efficiency and stable-emission-wavelength light-emission devices. (C) 2002 Elsevier Science B.V. All rights reserved.