Well Thickness and Doping Effects, and Room Temperature Emission Mechanisms in InGaN/GaN and GaN/AlGaN Multiple Quantum
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Mat. Res. Soc. Symp. Proc. Vol. 482 © 1998 Materials Research Society
GaN Well 3.441 cV
3.0 T=200K
/
.-. l5
0.5
0.0 60 A, the spectral peak position of the dominant emission line occurs even at a lower energy than that of the localized exciton emission line in the InGaN epilayers of the same InN mole fraction and is due to an impurity related transition, similar to the case of the 50 A GaN/AlGaN MQW sample. These results indicate once more that the empirical critical thickness value in the InGaN/GaN MQW system is also less than 40 A. Above the critical thickness, strain is relieved by the creation of a large density of misfit dislocations, which leads to undesirable optical properties. Our observation here is consistent with results reported by other groups. A critical 646
o
t(ns)
1
2
3
4
5
6
5
7
(0
N
GaN films grown with an AIN buffer
layer on sapphire substrate as by x-ray diffraction has determined been reported. 6
T- 10K
25 A InGaN/GaN MQW
1 It has also been
reported that there is no quantum
pi ayer
a
]
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