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Proceedings Paper

Irradiation effects of graphene-enhanced gallium nitride (GaN) metal-semiconductor-metal (MSM) ultraviolet photodetectors
Author(s): Heather C. Chiamori; Ruth Miller; Ateeq Suria; Nicholas Broad; Debbie G. Senesky
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Paper Abstract

Ultraviolet (UV) photodetectors are used for applications such as flame detection, space navigation, biomedical and environmental monitoring. Robust operation within large ranges of temperatures, radiation, salinity and/or corrosive chemicals require sensor materials with the ability to withstand and function reliably within these extreme harsh environments. For example, spacecraft can utilize a sun sensor (light-based sensor) to assist with determination of orientation and may be exposed to both ionizing radiation and extreme temperature swings during operation. Gallium nitride (GaN), a wide bandgap semiconductor material, has material properties enabling visible-blindness, tunable cutoff wavelength selection based on ternary alloy mole fraction, high current density, thermal/chemical stability and high radiation tolerance due to the strength of the chemical bond. Graphene, with outstanding electrical, optical and mechanical properties and a flat absorption spectrum from 300 to 2,500 nm, has potential use as a transparent conductor for GaN-based metal-semiconductor-metal (MSM) photodetectors. Here, graphene-enhanced MSM UV photodetectors are fabricated with transparent and conductive graphene interdigitated electrodes on thin film GaN-on-sapphire substrates serving as back-to-back Schottky contacts. We report on the irradiation response of graphene/GaN-based MSM UV photodetectors up to 750 krad total ionizing dose (TID) then tested under dark and UV light (365 nm) conditions. In addition, based on current-voltage measurements from 75 krad to 750 krad TID, calculated photodetector responsivity values change slightly by 25% and 11% at -5 V and -2 V, respectively. These initial findings suggest that graphene/GaN MSM UV photodetectors could potentially be engineered to reliably operate within radiation environments.

Paper Details

Date Published: 19 May 2015
PDF: 7 pages
Proc. SPIE 9491, Sensors for Extreme Harsh Environments II, 949107 (19 May 2015); doi: 10.1117/12.2178091
Show Author Affiliations
Heather C. Chiamori, Stanford Univ. (United States)
Ruth Miller, Stanford Univ. (United States)
Ateeq Suria, Stanford Univ. (United States)
Nicholas Broad, Stanford Univ. (United States)
Debbie G. Senesky, Stanford Univ. (United States)

Published in SPIE Proceedings Vol. 9491:
Sensors for Extreme Harsh Environments II
Debbie G. Senesky; Sachin Dekate, Editor(s)

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