Gain mechanism and carrier transport in high responsivity AlGaN-based solar blind metal semiconductor metal photodetectors

Rathkanthiwar, Shashwat and Kalra, Anisha and Solanke, Swanand V and Mohta, Neha and Muralidharan, Rangarajan and Raghavan, Srinivasan and Nath, Digbijoy N (2017) Gain mechanism and carrier transport in high responsivity AlGaN-based solar blind metal semiconductor metal photodetectors. In: JOURNAL OF APPLIED PHYSICS, 121 (16).

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Abstract

We report on the highest responsivity for III-nitride Metal Semiconductor Metal solar-blind photodetectors on sapphire. Devices on unintentionally doped AlGaN epilayers grown by Metal Organic Chemical Vapor Deposition exhibited sharp absorption cut-off in the range of 245-290 nm. Very high responsivity >5 A/W at 10V bias was achieved with visible rejection exceeding three orders of magnitude for front illumination. Compared to the responsivity values reported in the literature for state-of-the-art solar-blind photodetectors, this work presents the highest values of responsivity at a given bias and up to sub-250 nm detection threshold. The high responsivity is attributed to an internal gain mechanism operating on these devices. The reverse-bias leakage current across these samples was found to be dominated by thermionic field emission at low biases and Poole-Frenkel emission from a deep trap level (0.7 eV from the conduction band-edge for Al0.50Ga0.50N) at high biases. Published by AIP Publishing.

Item Type:	Journal Article
Publication:	JOURNAL OF APPLIED PHYSICS
Additional Information:	Copy right for this article belongs to the AMER INST PHYSICS, 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA
Department/Centre:	Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited:	03 Jun 2017 09:40
Last Modified:	03 Jun 2017 09:40
URI:	http://eprints.iisc.ac.in/id/eprint/57103

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