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Indexed by:期刊论文

Date of Publication:2018-02-25

Journal:JOURNAL OF ALLOYS AND COMPOUNDS

Included Journals:SCIE、EI

Volume:735

Page Number:1239-1244

ISSN No.:0925-8388

Key Words:InGaN; High indium content; Optical properties; Indium incorporation; MOCVD

Abstract:The optical properties of thick InGaN epilayers grown by metal-organic chemical vapor deposition with indium (In) content range from 10% to 42% were investigated. With the increase of In content, the crystal quality of InGaN epilayers significantly degraded, particularly at increasing the edge-type dislocations density for high In content InGaN. Combining high-resolution X-ray diffraction reciprocal space mapping, the splitting of the photoluminescence (PL) peak into several PL bands was found to be caused by compositional fluctuations rather than by the strain effects. Based on the PL and optical absorption spectra, the composition-dependent Stokes shift was observed and a linear relationship between Stokes shift and Urbach tailing energy was established. Additionally, a drop of In incorporation along the growth direction was observed in InGaN epilayers with high In content. Such drop behavior of In incorporation was attributed to the formation of In droplets, which offers a competing pathway for In incorporation by gathering the incoming In atoms hence causing a decrease in the surrounding In incorporation. This will present a broader view about the nature of InGaN alloys with high In content. (C) 2017 Elsevier B.V. All rights reserved.