Significant internal quantum efficiency enhancement of GaN/AlGaN multiple quantum wells emitting at ~350 nm via step quantum well structure design

Feng Wu, Haiding Sun, Idris A. Ajia, Iman S. Roqan, Daliang Zhang, Jiangnan Dai, Changqing Chen, Zhe Chuan Feng, Xiaohang Li

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

Significant internal quantum efficiency (IQE) enhancement of GaN/AlGaN multiple quantum wells (MQWs) emitting at similar to 350 nm was achieved via a step quantum well (QW) structure design. The MQW structures were grown on AlGaN/AlN/sapphire templates by metal-organic chemical vapor deposition (MOCVD). High resolution x-ray diffraction (HR-XRD) and scanning transmission electron microscopy (STEM) were performed, showing sharp interface of the MQWs. Weak beam dark field imaging was conducted, indicating a similar dislocation density of the investigated MQWs samples. The IQE of GaN/AlGaN MQWs was estimated by temperature dependent photoluminescence (TDPL). An IQE enhancement of about two times was observed for the GaN/AlGaN step QW structure, compared with conventional QW structure. Based on the theoretical calculation, this IQE enhancement was attributed to the suppressed polarization-induced field, and thus the improved electron-hole wave-function overlap in the step QW.
Original languageEnglish (US)
Pages (from-to)245101
JournalJournal of Physics D: Applied Physics
Volume50
Issue number24
DOIs
StatePublished - May 3 2017

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