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Effects of indium composition on the surface morphological and optical properties of InGaN/GaN heterostructures

Nur Atiqah Hamzah (Institute of Nano Optoelectronics Research and Technology (INOR), Universiti Sains Malaysia, Penang, Malaysia)
Mohd Ann Amirul Zulffiqal Md Sahar (Institute of Nano Optoelectronics Research and Technology (INOR), Universiti Sains Malaysia, Penang, Malaysia)
Aik Kwan Tan (Institute of Nano Optoelectronics Research and Technology (INOR), Universiti Sains Malaysia, Penang, Malaysia)
Mohd Anas Ahmad (Institute of Nano Optoelectronics Research and Technology (INOR), Universiti Sains Malaysia, Penang, Malaysia)
Muhammad Fadhirul Izwan Abdul Malik (Science and Engineering Research Centre (SERC), Engineering Campus, Universiti Sains Malaysia, Penang, Malaysia)
Chin Chyi Loo (Mechanical Engineering Discipline, School of Engineering, Monash University, Bandar Sunway, Selangor, Malaysia)
Wei Sea Chang (Mechanical Engineering Discipline, School of Engineering, Monash University, Bandar Sunway, Selangor, Malaysia)
Sha Shiong Ng (Institute of Nano Optoelectronics Research and Technology (INOR), Universiti Sains Malaysia, Penang, Malaysia)

Microelectronics International

ISSN: 1356-5362

Article publication date: 10 June 2022

Issue publication date: 2 January 2023

86

Abstract

Purpose

This study aims to investigate the effects of indium composition on surface morphology and optical properties of indium gallium nitride on gallium nitride (InGaN/GaN) heterostructures.

Design/methodology/approach

The InGaN/GaN heterostructures were grown on flat sapphire substrates using a metal-organic chemical vapour deposition reactor with a trimethylindium flow rate of 368  sccm. The indium composition of the InGaN epilayers was controlled by applying different substrate temperatures. The surface morphology and topography were observed using field emission scanning electron microscope (F.E.I. Nova NanoSEM 450) and atomic force microscopy (Bruker Dimension Edge) with a scanning area of 10 µm × 10 µm, respectively. The compositional analysis was done by Energy Dispersive X-Ray Analysis. Finally, the ultraviolet-visible (UV-Vis) spectrophotometer (Agilent Technology Cary Series UV-Vis-near-infrared spectrometer) was measured from 200 nm to 1500 nm to investigate the optical properties of the samples.

Findings

The InGaN/GaN thin films have been successfully grown at three different substrate temperatures. The indium composition reduced as the temperature increased. At 760 C, the highest indium composition was obtained, 21.17%. This result was acquired from the simulation fitting of ω−2θ scan on (0002) plane using LEPTOS software by Bruker D8 Discover. The InGaN/GaN shows significantly different surface morphologies and topographies as the indium composition increases. The thickness of InGaN epilayers of the structure was ∼300 nm estimated from the field emission scanning electron microscopy. The energy bandgap of the InGaN was 2.54 eV – 2.79 eV measured by UV-Vis measurements.

Originality/value

It can be seen from this work that changes in substrate temperature can affect the indium composition. From all the results obtained, this work can be helpful towards efficiency improvement in solar cell applications.

Keywords

Acknowledgements

This research was funded by Universiti Sains Malaysia (USM), Malaysia, through the Research University Individual Grant (Account Number: 1001/CINOR/8011127). The support given by USM and Collaborative Research in Engineering; Science & Technology Center is gratefully acknowledged.

Citation

Hamzah, N.A., Md Sahar, M.A.A.Z., Tan, A.K., Ahmad, M.A., Abdul Malik, M.F.I., Loo, C.C., Chang, W.S. and Ng, S.S. (2023), "Effects of indium composition on the surface morphological and optical properties of InGaN/GaN heterostructures", Microelectronics International, Vol. 40 No. 1, pp. 8-16. https://doi.org/10.1108/MI-03-2022-0042

Publisher

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Emerald Publishing Limited

Copyright © 2020, Emerald Publishing Limited

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