Electronic surface, optical and electrical properties of p – GaN activated via in-situ MOCVD and ex-situ thermal annealing in InGaN/GaN LED

Mahat, Mohamad Raqif and Talik, Noor Azrina and Abd Rahman, Mohd Nazri and Anuar, Mohd Afiq and Allif, Kamarul and Azman, Adreen and Nakajima, Hideki and Shuhaimi, Ahmad and Abd Majid, Wan Haliza (2020) Electronic surface, optical and electrical properties of p – GaN activated via in-situ MOCVD and ex-situ thermal annealing in InGaN/GaN LED. Materials Science in Semiconductor Processing, 106. p. 104757. ISSN 1369-8001, DOI https://doi.org/10.1016/j.mssp.2019.104757.

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Official URL: https://doi.org/10.1016/j.mssp.2019.104757


Electronic surface properties, optical and electrical characteristics of p-type Mg-doped Gallium Nitride (p-GaN) activated under different thermal annealing condition were investigated. In this work, p-GaN samples were subjected to in-situ and ex-situ thermal annealing process at 650 °C in Nitrogen (N2) rich condition. In-situ annealing process took place in Metal Oxide Chemical Vapor Deposition (MOCVD) chamber while ex-situ annealing process was carried out in the conventional oven. X-Ray and Ultraviolet Photoemission Spectroscopy (XPS/UPS) were used to observe the energy alignment of the p-GaN surface. From PES spectra, the sample subjected to in-situ thermal annealing shown to exhibit lower surface bend bending of 0.28 eV as compared to ex-situ thermal annealing activation with 0.45 eV band bending. This result is in agreement with specific contact resistance measurement that shows in-situ sample exhibits lower resistance resulted in better carrier injection from metal to p-GaN. Photoluminescence (PL) spectra elucidates that in-situ sample has a good surface quality with less nitrogen related vacancies (VN) formed on the p-GaN surface. All these results are further proved with the higher output power from LED with in-situ annealing. At 20 mA, in-situ sample shown an increment of ~14% light output power compared to ex-situ sample. Results obtained in this work suggest that the thermal activation condition for p-GaN activation process plays an active role on the surface quality as well as the energy alignment of the film surface and shows the potential of in-situ p-GaN activation for tunnel junction structure. © 2019 Elsevier Ltd

Item Type: Article
Funders: Malaysia Ministry of Education (MOE) via Long-term Research Grant (LRGS) LR001A-2016A, “Wide Band Gap Semiconductor” Grant
Uncontrolled Keywords: Electrical characteristic; Junction structure; Light output power; Optical and electrical properties; Photoluminescence spectrum; Situ thermal annealing; Specific contact resistances; Ultraviolet photoemission spectroscopy
Subjects: Q Science > Q Science (General)
Q Science > QC Physics
Divisions: Faculty of Science > Department of Physics
Depositing User: Mr. Faizal Hamzah
Date Deposited: 17 May 2011 02:37
Last Modified: 11 Nov 2019 05:52
URI: http://eprints.um.edu.my/id/eprint/1255

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