High-Performance Ultraviolet Photodetector Based on Graphene Quantum Dots Decorated ZnO Nanorods/GaN Film Isotype Heterojunctions

Abstract

A novel isotype heterojunction ultraviolet photodetector was fabricated by growing n-ZnO nanorod arrays on n-GaN thin films and then spin-coated with graphene quantum dots (GQDs). Exposed to UV illumination with a wavelength of 365 nm, the time-dependent photoresponse of the hybrid detectors manifests high sensitivity and consistent transients with a rise time of 100 ms and a decay time of 120 ms. Meanwhile, an ultra-high specific detectivity (up to ~ 1012 Jones) and high photoresponsivity (up to 34 mA W−1) are obtained at 10 V bias. Compared to the bare heterojunction detectors, the excellent performance of the GQDs decorated n-ZnO/n-GaN heterostructure is attributed to the efficient immobilization of GQDs on the ZnO nanorod arrays. GQDs were exploited as a light absorber and act like an electron donor to effectively improve the effective carrier concentration in interfacial junction. Moreover, appropriate energy band alignment in GQDs decorated ZnO/GaN hybrids can also be a potential factor in facilitating the UV-induced photocurrent and response speed.

Graphene Quantum Dot-Sensitized ZnO-Nanorod/GaN-Nanotower Heterostructure-Based High-Performance UV Photodetectors

“…Moreover, the presence of GQDs also helps in faster collection of the photogenerated charge carrier, leading to reduced response time. Lately, Liu et al have reported a GQD-sensitized ZnO-NRs/GaN-film (metal organic chemical vapor deposition) heterostructure-based UV photodetector; however, the reported responsivity of the detector is very low (∼34 mA/W) even at a very high applied bias voltage of 10 V. 31 In this work, we have reported the fabrication of a highperformance UV photodetector utilizing the unique ZnO-NR/ GaN-NT/heterostructure sensitized with GQDs. The analysis exhibits the cumulative effect of the ZnO/GaN heterointerface junction (their nanostructures implicated higher surface to volume ratio) and extra photoinduced charge carriers via GQD sensitization with efficient transport by a ■ METHODS/EXPERIMENTAL SECTION ZnO-NR/GaN-NT Heterostructure.…”

Synthesis, Applications, and Prospects of Graphene Quantum Dots: A Comprehensive Review

“…In another work, a high‐performance GQD‐decorated ZnO nanorods/GaN film was fabricated for UV monitoring. [ 217 ] In this heterojunction, GQDs act as electron donors and contribute to the enhancement of the active carrier concentration.…”

Using Novel Semiconductor Features to Construct Advanced ZnO Nanowires-Based Ultraviolet Photodetectors: A Brief Review

“…Meanwhile, an ultra-high specific detectivity of 10 12 Jones was obtained. The improved performance was due to the rapid separation of photogenerated electrons and holes and efficient carrier migration [122].…”