Optimizing GaN/AlGaN multiple quantum well structures by time-resolved photoluminescence

Jing Li; Kecai Zeng; Eunjoo Shin; Jing Yu Lin; Hongxing Jiang

doi:10.1117/12.424744

23 April 2001 Optimizing GaN/AlGaN multiple quantum well structures by time-resolved photoluminescence

Jing Li, Kecai Zeng, Eunjoo Shin, Jing Yu Lin, Hongxing Jiang

Proceedings Volume 4280, Ultrafast Phenomena in Semiconductors V; (2001) https://doi.org/10.1117/12.424744
Event: Symposium on Integrated Optics, 2001, San Jose, CA, United States

Abstract

We present the results of picosecond time-resolved photoluminescence (PL) measurements for GaN/Al_xGa_1-xN MQWs with varying structural parameters, grown by metalorganic chemical vapor deposition under the optimal GaN-like growth conditions. We have shown that the optimal GaN/AlGaN (x approximately 0.2) MQW structures for UV light emitter applications are those with well widths ranging from 12 and 42 angstroms and barrier widths ranging from 40 to 80 angstroms. The decreased quantum efficiency in GaN/Al_xGa_1-xN MQWs with well width L_W < 12 angstroms is due to the enhanced carrier leakage to the underlying GaN epilayers, while the decreased quantum efficiency in MQWs with well width L_W > 42 angstroms is associated with an increased nonradiative recombination rate as L_W approaching the critical thickness of MQWs. For the barrier width dependence, when the barrier width is below the critical thickness, the nonradiative recombination rate increases with a decrease of the barrier width due to the enhanced possibilities of the electron and hole wavefunctions at the interfaces as well as in the AlGaN barriers. On the other hand, the misfit dislocation density increases as the barrier width approaches the critical thickness, which can result in an enhanced nonradiative interface recombination rate. Our optimized GaN/Al_xGa_1-xN MQW structures exhibited extremely high quantum efficiencies as well as a ratio of well emission intensity to barrier emission intensity exceeding 10⁴.

Citation Download Citation

Jing Li, Kecai Zeng, Eunjoo Shin, Jing Yu Lin, and Hongxing Jiang "Optimizing GaN/AlGaN multiple quantum well structures by time-resolved photoluminescence", Proc. SPIE 4280, Ultrafast Phenomena in Semiconductors V, (23 April 2001); https://doi.org/10.1117/12.424744

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