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Chemical mapping of indium rich quantum dots in InGaN/GaN quantum wells

Published online by Cambridge University Press:  21 March 2011

N Sharma ,
H K Cho ,
J Y Lee  and
C J Humphreys
N Sharma
Affiliation:
Department of Metallurgy and the Science of Materials, University of Cambridge, Pembroke Street, Cambridge, CB2 3QZ, U.K.
H K Cho
Affiliation:
Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, 373-1 Kusong-dong,Yusong-gu, Taejon, 305-701, South Korea
J Y Lee
Affiliation:
Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, 373-1 Kusong-dong,Yusong-gu, Taejon, 305-701, South Korea
C J Humphreys
Affiliation:
Department of Metallurgy and the Science of Materials, University of Cambridge, Pembroke Street, Cambridge, CB2 3QZ, U.K.
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Abstract

Indium clustering in InGaN/GaN multiple quantum wells (MQWs) is believed to be responsible for the high luminescent efficiency of GaN based light emitting diodes. In this paper we show that substantial clustering can be induced by reducing to zero the interruption time between growth of the GaN barrier layer on the InGaN quantum well. Photoluminescence (PL) shows that this has the effect of increasing the luminescence intensity and decreasing the band gap energy (higher indium concentration). The clusters or quantum dots were examined and quantified by energy filtered transmission electron microscopy (EFTEM), which was used to form chemical distribution maps of indium, gallium and nitrogen. In this paper we will show that this technique can accurately calculate the indium concentration and distribution in the quantum wells. The calculations show that InxGa1−xN quantum dots (width = 1.3nm) exhibit an In concentration of up to x = 0.5, which are embedded in a quantum well matrix with x = 0.05.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 667: Symposium G – Luminescence and Luminescent Materials , 2001 , G6.7
Copyright
Copyright © Materials Research Society 2001

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References

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