Ultrawide Band Gap Oxide Nanodots (E_g > 4.8 eV) for a High-Performance Deep Ultraviolet Photovoltaic Detector

Abstract

Recently, deep ultraviolet (DUV) detectors based on gallium oxide (Ga2O3) have become promising in industrial and aerospace applications because of their inherently ultrawide band gaps (4.5–4.9 eV). Because most of them are difficult to be prepared, the lattice mismatch with the substrate and the expensive cost have to be taken into consideration. Because of such problems, the solution-processible nanodots (NDs) with ultrasmall size provide a solution. Here, we propose to use γ-Ga2O3 NDs as the DUV-sensitive layer to construct a DUV p–i–n-type detector with photovoltaic properties (p-graphene/γ-Ga2O3 NDs/n-SiC). The device exhibits a high photoresponsivity (5.8 mA/W) and detectivity (7.6 × 1010 jones) with a 250 nm source illumination under 0 V bias. Moreover, the DUV/UV injection ratio (R 250/R 360) reaches 103. These results demonstrate a new way to manufacture low-cost, high-performance DUV detectors based on γ-Ga2O3.

A Strategic Review on Gallium Oxide Based Deep‐Ultraviolet Photodetectors: Recent Progress and Future Prospects

“…Kan et al. [ 106 ] have fabricated a deep‐UV p–i–n type photodetector using p‐graphene/γ‐Ga 2 O 3 nanodots/n‐SiC with a self‐powered photoresponsivity of 5.8 mA W −1 . Similarly, high quality nanospheres of γ‐Ga 2 O 3 with a high specific surface area were synthesized and employed in making a device with PDCR of 2.29 × 10 3 by Ruan et al.…”

“…Reproduced with permission. [ 106 ] Copyright 2020, American Chemical Society. d) Schottky photodiode employs the use of a Schottky barrier at the metal–semiconductor interface leading to an even lesser dark current than the traditional photodiode.…”

“…Keeping this in mind, a few p–i–n structured deep UV detectors have been developed employing heterostructures with gallium oxide. [ 106,140–141 ] Jian et al. [ 141 ] used a vapor cooling condensation system for depositing p‐ZnO:LiNO 3 , i‐Ga 2 O 3 , and n‐Ga 2 O 3: Si layers on sapphire substrates to fabricate solar‐blind p–i–n DUV photodetectors.…”

“…Finally, the photogenerated holes and electrons are collected at the electrodes to build a photo voltage thereby resulting in a stable photocurrent. [ 106 ]…”

“…Reproduced with permission. [ 106 ] Copyright 2020, American Chemical Society. b,c) TEM of the amorphous Ga 2 O 3 core–shell nanoparticles with elemental mapping and the corresponding device performance.…”