Spectrally Selective and Highly Sensitive UV Photodetection with UV‐A,C Band Specific Polarity Switching in Silver Plasmonic Nanoparticle Enhanced Gallium Oxide Thin‐Film

Abstract

Traditional photodetectors generally show a unipolar photocurrent response when illuminated with light of wavelength equal or shorter than the optical bandgap. Here, it is reported that a thin film of gallium oxide (GO) decorated with plasmonic nanoparticles, surprisingly, exhibits a change in the polarity of the photocurrent for different UV bands. Silver nanoparticles (Ag NPs) are vacuum‐deposited onto β‐Ga2O3 and the AgNP@GO thin films show a record responsivity of 250 A W−1, which significantly outperforms bare GO planar photodetectors. The photoresponsivity reverses sign from +157 µA W−1 in the UV‐C band under unbiased operation to −353 µA W−1 in the UV‐A band. The current reversal is rationalized by considering the charge dynamics stemming from hot electrons generated when the incident light excites a local surface plasmon resonance in the Ag nanoparticles. The Ag nanoparticles improve the external quantum efficiency and detectivity by nearly one order of magnitude with high values of 1.2 × 105 and 3.4 × 1014 Jones, respectively. This plasmon‐enhanced solar blind GO detector allows UV regions to be spectrally distinguished, which is useful for the development of sensitive dynamic imaging photodetectors.

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

“…This requires careful selection of the chosen material and the growth process. Plasmonics-based enhancement in performance has been reported [254][255][256] and further work is required in this direction to maximize the effect. Hot electron carrier injection [223] is another phenomenon in which hot carriers are generated form the nonradiative decay of surface plasmons.…”

A versatile photodetector assisted by photovoltaic and bolometric effects

“…First, the VO 2 film was patterned by UV photolithography and Ar plasma etching. MoTe 2 flakes were exfoliated by scotch tape onto polydimethylsiloxane and transferred to the top of etched VO 2 by dry transfer 12 . Polymethyl methacrylate and conductive ink were spin-coated (4000 rpm for 45 s) on the substrate for electron beam lithography to define electrodes.…”

“…The thermal detectors also include thermopiles (Pt-Ir), bolometers (VO 2 , α-Si), and pyroelectric detectors (LiTaO 3 , PVDF) 2,3,5,6 . Recently, the emergence of detectors based on low-dimensional materials [7][8][9][10][11][12] , such as quantum dots, nanowires, nanoflakes, and nanofilms, has led to a boom in the development of excellent photodetectors. Nanostructured materials with reduced physical size and unique band structure bring about incredible performance compared to traditional materials.…”

Organic passivation of Al0.5Ga0.5N epilayers using self-assembled monolayer of Zn(II) porphyrin for improved solar-blind photodetector performance

“…AlxGa1-xN, AlN, SiC, Ga2O3 and diamond are suitable for fabricating such photodetectors. [8][9][10] Out of these semiconductors, AlxGa1-xN, the alloy of GaN and AlN, has a direct bandgap which can be tuned from 3.4 eV (x=0) to 6.2 eV (x=1). The alloys with higher concentrations of Al (x ≥ 0.5) are suitable for realizing solar-blind operation.…”