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

K. Prabakaran, M. Jayasakthi, S. Surender, S. Pradeep, S. Sanjay, Raju Ramesh, M. Balaji, Nicolas Gautier, K. Baskar

Research output: Contribution to journalArticleScientificpeer-review

2 Citations (Scopus)

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.
Original languageEnglish
Pages (from-to)993-999
Number of pages7
JournalApplied Surface Science
Volume476
DOIs
Publication statusPublished - 15 May 2019
MoE publication typeA1 Journal article-refereed

Keywords

  • InGaN
  • Multiple quantum well
  • Photoluminescence
  • V-pits
  • Nanostructures

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