Ramesh, Ch. and Tyagi, P. and Bhattacharyya, Biplab and Husale, Sudhir and Maurya, K. K. and Kumar, M. Senthil and Kushvaha, S. S. (2019) Laser molecular beam epitaxy growth of porous GaN nanocolumn and nanowall network on sapphire (0001) for high responsivity ultraviolet photodetectors. Journal of Alloys and Compounds, 770. 572-581. ISSN 0925-8388

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Abstract

We report on high-responsivity metal-semiconductor-metal (MSM) structure based ultraviolet (UV) GaN photodetectors fabricated on various GaN nanostructures such as porous nanocolumn network (PNCN), nanowall networks (NWNs), and granular and compact thin films. Different GaN nanostructures were hetero-epitaxially grown on c-sapphire using laser molecular beam epitaxy by tuning the AIN buffer layer growth parameters. High resolution x-ray rocking curve measurements indicate that the crystalline quality of GaN critically depends on the selection of AIN buffer layer growth conditions such as type of ablation target and growth temperature. The porous GaN nanostructures revealed a nearly stress-free wurtzite structure as deduced by Raman spectroscopy measurements. Room temperature photoluminescence spectroscopy showed that the GaN films possess a near band emission (NBE) peak at similar to 3.39 eV along with a broad yellow luminescence (YL) with maxima at 2.25 eV. For GaN PNCN and NWN structures, the NBE-to-YL emission ratio is more than an order higher compared to the GaN films. The fabricated MSM based UV-detector on GaN PNCN and NWN exhibited a high photo-responsivity of similar to 27.72 and 24.8 A/W, respectively, under 2 V applied bias at room temperature. The GaN PNCN and NWN nanostructures with excellent photo-responsivity and optical quality prove to be promising candidates for the fabrication of efficient UV photodetectors due to their continuity in lateral direction, high surface area-to-volume ratio and tailored surfaces.

Item Type:	Article
Additional Information:	Copyright for this article belongs to M/s Elsevier.
Subjects:	Chemistry > Physical Chemistry Materials Science Metallurgy & Metallurgical Engineering
Divisions:	UNSPECIFIED
Depositing User:	Mr. Yogesh Joshi
Date Deposited:	19 Aug 2026 11:34
Last Modified:	19 Aug 2026 11:34
URI:	https://npl.csircentral.net/id/eprint/4271

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