Structural, morphological, optical and electrical characterization of InGaN/GaN MQW structures for optoelectronic applications

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2019-05-15
Major/Subject
Mcode
Degree programme
Language
en
Pages
7
993-999
Series
Applied Surface Science, Volume 476
Abstract
InGaN/GaN multiple quantum well (MQW) structures were grown on c-plane sapphire substrate using metal organic chemical vapour deposition technique by varying the MQW periods. The indium composition and thickness were estimated using high-resolution X-ray diffraction. InGaN well, GaN barriers and Indium composition were estimated as 3 nm, 18 nm and 16–18% using epitaxy smooth fit software. Reciprocal space mapping revealed that InGaN/GaN MQW samples were coherently strained. High-resolution transmission electron microscopy images confirmed good interface between the InGaN/GaN MQW structures. Atomic force microscopy and scanning electron microscopy exhibit decrease in the surface roughness with increase in the number of InGaN/GaN MQW periods with respect to the number of defects comprising of threading dislocations and hexagonal V-pits. Self-organized In(Ga)N like nanostructures with spiral growth mechanism was also observed due to the low temperature growth of p-GaN layer. The photoluminescence spectra of the MQWs showed a red-shift when the number of QW periods was increased due to quantum confined stark effect. Hall Effect measurement displayed good semiconducting behavior in the InGaN/GaN MQW structures. The carrier concentration values also emphasized adequate variations when number of periods was increased.
Description
Keywords
InGaN, Multiple quantum well, Photoluminescence, V-pits, Nanostructures
Other note
Citation
Prabakaran, K, Jayasakthi, M, Surender, S, Pradeep, S, Sanjay, S, Ramesh, R, Balaji, M, Gautier, N & Baskar, K 2019, ' Structural, morphological, optical and electrical characterization of InGaN/GaN MQW structures for optoelectronic applications ', Applied Surface Science, vol. 476, pp. 993-999 . https://doi.org/10.1016/j.apsusc.2019.01.156