Time-resolved photoluminescence measurements of quantum dots in InGaN multiple quantum wells and light-emitting diodes
We have used time-resolved photoluminescence to examine InGaN/GaN multiple quantum wells (MQWs) and light-emitting diodes (LEDs) before the final stages of processing at room temperature. The photoluminescence kinetics are well described by a stretched exponential exp[−(t/τ)β], indicating significan...
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Veröffentlicht in: | Journal of applied physics 1999-07, Vol.86 (2), p.1114-1118 |
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Hauptverfasser: | , , , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | We have used time-resolved photoluminescence to examine InGaN/GaN multiple quantum wells (MQWs) and light-emitting diodes (LEDs) before the final stages of processing at room temperature. The photoluminescence kinetics are well described by a stretched exponential exp[−(t/τ)β], indicating significant disorder in the material. We attribute the disorder to nanoscale quantum dots of high local indium concentration. For the three MQWs examined, the stretching parameter β and the stretched exponential lifetime τ were found to vary with emission energy. The stretching parameter β for the emission peak of the three MQWs was observed to increase from 0.75 to 0.85 with apparently increasing indium phase segregation. A higher degree of indium phase segregation is consistent with more isolated quantum dots inside the two-dimensional quantum well. The time-resolved photoluminescence from a LED wafer, before the final stages of processing, suggests the importance of quantum dots of high indium concentration on the LED operation. |
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ISSN: | 0021-8979 1089-7550 |
DOI: | 10.1063/1.370865 |