Carrier Dynamics in UV InGaN Multiple Quantum Well Inverted Hexagonal Pits

abstract

The emission and recombination characteristics of UV or blue light emission from InGaN/GaN quantum well (QW) structures influenced by V-shaped pits have been investigated by near-field and time-resolved photoluminescence measurements. Localization of charge carriers due to the potential barriers caused by the V-shaped pit formation is observed to be modified by thermal excitation. Temperature dependence of recombination dynamics shows evidence of a more complex potential barrier produced by the inverted hexagonal pits embedded within the multiple QWs. The emission from the narrow V-shaped pit QWs shows anomalous temperature dependence behavior that is significantly different from the emission from c-plane QWs. The carrier recombination process in c-plane QWs is significantly longer similar to 5 ns compared to the similar to 1.5 ns in V-shaped pit QWs at low temperatures due to the larger piezoelectric fields in wider wells. At room temperature, the recombination lifetimes are comparable due to increased carrier separation and delocalization within the V-shaped pit QWs.

keywords

LIGHT-EMITTING-DIODES; SURFACE

subject category

Engineering; Optics; Physics

authors

Llopis, A; Lin, J; Li, JY; Pereira, S; Neogi, A

our authors

acknowledgements

This work was supported by the National Science Foundation Major Research Instrumentation program and International Research Experience for Students program.

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