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Sub-bandgap optical absorption processes in 300-nm-thick Al1−xInxN alloys grown on a c-plane GaN/sapphire template.

Authors :
Imai, Daichi
Murakami, Yuto
Toyoda, Hayata
Noda, Kouki
Masaki, Kyosuke
Kubo, Kazutoshi
Nomura, Mayu
Miyoshi, Makoto
Miyajima, Takao
Takeuchi, Tetsuya
Source :
Journal of Applied Physics; 1/21/2024, Vol. 135 Issue 3, p1-8, 8p
Publication Year :
2024

Abstract

We investigate the sub-bandgap optical absorption (SOA) in 300-nm-thick Al<subscript>1−x</subscript>In<subscript>x</subscript>N alloys used in cladding layers of edge-emitting laser diodes and distributed Bragg reflectors of vertical-cavity surface-emitting lasers. Al<subscript>1−x</subscript>In<subscript>x</subscript>N alloys, with indium content x ranging from 0.114 to 0.185, were grown by metal-organic chemical vapor deposition on a c-plane GaN/sapphire template. SOAs on 300-nm-thick thin films were characterized using photothermal deflection spectroscopy (PDS). Thermal emission, such as nonradiative recombination with phonon emission, is the dominant energy relaxation process occurring after SOA in Al<subscript>1−x</subscript>In<subscript>x</subscript>N alloys. The absorption coefficient of the SOA was estimated to be 0.6–7.0 × 10<superscript>3 </superscript>cm<superscript>−1</superscript> in these samples by combining PDS and spectroscopic ellipsometry. The drastic increase in the SOA, when x exceeded the lattice-matched composition of the GaN/sapphire template, indicates that impurities, vacancy-type defects, and their complexes with increasing x are possible candidates that result in SOA in Al<subscript>1−x</subscript>In<subscript>x</subscript>N alloys. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00218979
Volume :
135
Issue :
3
Database :
Complementary Index
Journal :
Journal of Applied Physics
Publication Type :
Academic Journal
Accession number :
174910831
Full Text :
https://doi.org/10.1063/5.0181231