GaN-HEMT on Si as a robust visible-blind UV detector with high responsivity

Varghese, Arathy, Eblabla, Abdalla ORCID: https://orcid.org/0000-0002-5991-892X, Wu, Zehao, Ghozati, Seyed Urman ORCID: https://orcid.org/0000-0002-6014-5223 and Elgaid, Khaled ORCID: https://orcid.org/0000-0003-3265-1097 2022. GaN-HEMT on Si as a robust visible-blind UV detector with high responsivity. IEEE Sensors Journal 22 (12) , pp. 12307-12313. 10.1109/JSEN.2022.3170653

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Abstract

This work presents performance evaluation of GaN High Electron Mobility Transistor (HEMT) based ultraviolet (UV) detector on Si substrate. In addition to the fabrication and characterization, a systematic study is presented here using simulations extensively to investigate the UV detection mechanism. Output current has been chosen as the sensing metric, the fabricated device exhibits a high UV responsivity of 1.62 x 107 A/W at 2.5 x 10-10 W, VGS=0.5 V. Simulations have been done using optical modules available in Silvaco ATLAS TCAD to analyze the energy band bending, Two-Dimensional Electron Gas (2DEG), channel potentials and electric fields in the device. This model can aid in systematic study of HEMT based detectors in terms of dimensional and epi layer design optimizations for sensitivity enhancements. The UV response of the device is found to decrease as the wavelength approaches the visible light wavelength. This makes the photodetectors blind to visible light ensuring selective detection of UV wavelengths. It has been observed that as the area for UV absorption is increased by increasing the W/L ratio, the increases. For a W/L ratio of 100, the detector exhibits a responsivity of 1.86 x 107 A/W.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Engineering
Publisher:	Institute of Electrical and Electronics Engineers
ISSN:	1530-437X
Date of First Compliant Deposit:	7 June 2022
Last Modified:	11 Jan 2024 09:28
URI:	https://orca.cardiff.ac.uk/id/eprint/149919

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