UV detector based on InAlN/GaN-on-Si HEMT stack with photo-to-dark current ratio > 10(7)

Kumar, Sandeep and Pratiyush, Anamika Singh and Dolmanan, Surani B and Tripathy, Sudhiranjan and Muralidharan, Rangarajan and Nath, Digbijoy N (2017) UV detector based on InAlN/GaN-on-Si HEMT stack with photo-to-dark current ratio > 10(7). In: APPLIED PHYSICS LETTERS, 111 (25).

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Abstract

We demonstrate an InAlN/GaN-on-Si high electron mobility transistor based UV detector with a photo-to-dark current ratio of > 10(7). The Ti/Al/Ni/Au metal stack was evaporated and thermal annealed rapidly for Ohmic contacts to the 2D electron gas (2DEG) at the InAlN/GaN interface, while the channelthornbarrier was recess etched to a depth of 20 nm to pinch-off the 2DEG between Source-Drain pads. A spectral responsivity (SR) of 32.9 A/W at 367 nm was measured at 5V. A very high photo-to-dark current ratio of > 10(7) was measured at a bias of 20 V. The photo-to-dark current ratio at a fixed bias was found to be decreasing with an increase in the recess length of photodetectors. The fabricated devices were found to exhibit a UV-to-visible rejection ratio of > 10(3) with a low dark current of < 32 pA at 5V. Transient measurements showed rise and fall times in the range of 3-4 ms. The gain mechanism was investigated, and carrier lifetimes were estimated which matched well with those reported elsewhere. Published by AIP Publishing.

Item Type:	Journal Article
Publication:	APPLIED PHYSICS LETTERS
Publisher:	10.1063/1.5004024
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:	12 Jan 2018 09:04
Last Modified:	12 Jan 2018 09:04
URI:	http://eprints.iisc.ac.in/id/eprint/58687

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