Article
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Preserved in Portico This version is not peer-reviewed
High Responsivity in GaN Ultraviolet Photodetector Achieved by Growing on a Periodic Trapezoid Column-Shape Patterned Sapphire Substrate
Version 1
: Received: 30 September 2016 / Approved: 30 September 2016 / Online: 30 September 2016 (09:40:28 CEST)
Version 2 : Received: 18 October 2016 / Approved: 18 October 2016 / Online: 18 October 2016 (08:19:48 CEST)
Version 2 : Received: 18 October 2016 / Approved: 18 October 2016 / Online: 18 October 2016 (08:19:48 CEST)
A peer-reviewed article of this Preprint also exists.
Abstract
GaN ultraviolet photodetector with metal-semiconductor-metal structure is achieved by growing on a periodic trapezoid column-shape patterned sapphire substrate using metalorganic chemical vapor deposition. Under 5-V reverse bias, the photodetector fabricated on such patterned sapphire substrate exhibits a lower dark current, a higher photocurrent, and a 476 % enhancement in the maximum responsivity as compare with those of the photodetector fabricated on conventional flat sapphire substrate. It is also found that the much larger UV-to-visible rejection ratio and the fact that responsivity drops in a smaller cut-off region are observed from photodetector fabricated by using a periodic trapezoid column-shape patterned sapphire substrate. These phenomena may all be attributed to the reduction of threading dislocation density and the improved quality of GaN film, as well as the internal reflection and/or scattering effect on the interface between GaN film and the periodic trapezoid column-shape pattern of the substrate.
Keywords
GaN ultraviolet photodetector; periodic trapezoid column-shape patterned sapphire substrate; responsivity; UV-to-visible rejection ratio
Subject
Chemistry and Materials Science, Other
Copyright: This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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