pp. 363-370
S&M1328 Research Paper of Special Issue https://doi.org/10.18494/SAM.2017.1517 Published: April 19, 2017 High Responsivity in GaN Ultraviolet Photodetector Grown on a Periodic Trapezoid-Column Patterned Sapphire Substrate [PDF] Kuan-Ting Liu, Shoou-Jinn Chang, and Sean Wu (Received August 30, 2016; Accepted January 24, 2017) Keywords: GaN ultraviolet photodetector, metal-semiconductor-metal, periodic trapezoid column-shaped patterned sapphire substrate, responsivity, UV-to-visible rejection ratio
A GaN ultraviolet (UV) photodetector with a metal-semiconductor-metal structure is grown on a periodic trapezoid-column patterned sapphire substrate by metalorganic chemical vapor deposition. Under 5 V reverse bias, the photodetector fabricated on such a patterned sapphire substrate exhibits a lower dark current, a higher photocurrent, a much larger UV-to-visible rejection ratio, and a 476% enhancement in the maximum responsivity than those of the photodetector fabricated on a conventional flat sapphire substrate. These phenomena may all be attributed to the reduction in threading dislocation density and the greater number of photogenerated carriers caused by the improved quality of the GaN film, as well as the reflection and/or scattering of unabsorbed photons on the interface between the GaN film and the periodic trapezoid-column pattern of the substrate.
Corresponding author: Kuan-Ting LiuCite this article Kuan-Ting Liu, Shoou-Jinn Chang, and Sean Wu, High Responsivity in GaN Ultraviolet Photodetector Grown on a Periodic Trapezoid-Column Patterned Sapphire Substrate, Sens. Mater., Vol. 29, No. 4, 2017, p. 363-370. |