Optical Analyses of the Emission Efficiencies of the InGaN/GaN Quantum Wells under the Conditions of Different p-GaN Thicknesses in Light-emitting Diodes
Date Issued
2011
Date
2011
Author(s)
Chen, Kuan-Yu
Abstract
In this study, we demonstrate the results of temperature-dependent photoluminescence, time-resolved photoluminescence, and wavelength-dependent TRPL, electroluminescence, and cathodoluminescence measurement results of the quantum wells of different samples. The optimization of the thickness of the high-temperature grown p-GaN layer for maximizing the QW internal quantum efficiency (IQE) and minimizing the device resistance in an InGaN/GaN QW light-emitting diode (LED) is demonstrated. During the growth of the p-AlGaN electron-blocking layer and p-GaN layer, the QWs are thermally annealed to first enhance carrier localization by reshaping the structures of indium-rich clusters before the optimized p-GaN thickness is reached. Beyond this point, the carrier localization effect becomes weakened, leading to lower IQE. Among the LED samples of different p-GaN thicknesses, the one with the highest IQE has the lowest device resistance. With a thicker p-GaN layer, the LED device resistance can be strongly affected by the QW crystal quality.
Subjects
Optical Analyses
InGaN
GaN
Quantum Wells
p-GaN
Light-emitting Diodes
Type
thesis
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