報告人：洪國慶
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Outline
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Introduction
Experimental Details
Results And Discussion
Conclusion
References
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Introduction(1/2)
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The peak internal quantum efficiency (IQE) of green LEDs is significantly lower than
that of shorter wavelength InAlGaN-based blue and longer wavelength InAlGaP-based
red LEDs .The efficiency of green LEDs at high drive currents decreases with increasing
injection current more significantly than in blue LEDs
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The fundamental mechanism that is responsible for efficiency-droop is a matter of
debate, electron leakage however has been claimed as an important mechanism resulting
in efficiency droop
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AlGaN electron blocking layer (EBL) is employed for the suppression of electron
leakage in most GaN based LED structures . However, an AlGaN EBL is not sufficiently
effective in blocking the leakage attributed to the large polarization fields at the interface
of the GaN barrier and the AlGaN
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Introduction(2/2)
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In recent studies, it has been reported that the efficiency and electron leakage characteristics depend
strongly on the thickness of an undoped GaN layer between the MQW active regions and the p-GaN layer
without p-AlGaN EBL for blue LEDs
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The theory shows that the electron leakage is suppressed as the thickness of the undoped GaN interlayer
decreases, whereas the quality of the active region deteriorates due to the increased Mg diffusion from the
p-GaN to MQW layers
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In this letter, we proposed low temperature (LT) GaN interlayer green LED structures that possess varied
doping depth in the LT interlayer. High efficiency is expected from the LED structure with an optimized
doping profile, where the electron leakage is suppressed and Mg diffusion is minimized
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