Ultrahigh EQE (15%) Solar‐Blind UV Photovoltaic Detector with Organic–Inorganic Heterojunction via Dual Built‐In Fields Enhanced Photogenerated Carrier Separation Efficiency Mechanism

Abstract

A new strategy of constructing an additional heterojunction on the surface of epitaxially grown Ga 2 O 3 film with a distorted lattice is proposed to solve the problem of low external quantum efficiency (EQE) in traditional Ga 2 O 3 heterojunction photovoltaic devices. Experimentally, an organic-inorganic hybrid poly(3,4-ethylenedioxythiophene):polystyrene sulfonate/Ga 2 O 3 /p-type Si solar-blind ultraviolet (SBUV) photovoltaic detector is constructed to achieve an ultrahigh EQE of ≈15% at 0 V bias, which is 1-2 orders of magnitude higher than that of the Ga 2 O 3 photovoltaic devices reported previously. Here, an enhanced mechanism of photogenerated carrier separation efficiency induced by dual built-in fields is proposed to explain the high EQE of Ga 2 O 3 SBUV photovoltaic devices. In addition, the organic-inorganic hybrid detector displays a high SBUV-visible rejection ratio (R 255 nm /R 405 nm of ≈450) and fast response speed (rise time of 60 ms and decay time of 88 ms). All these results indicate that the strategy proposed could provide reference for the fabrication of high-performance Ga 2 O 3 SBUV photovoltaic detectors.

Metalorganic Chemical Vapor Deposition Heteroepitaxial β‐Ga2O3 and Black Phosphorus Pn Heterojunction for Solar‐Blind Ultraviolet and Infrared Dual‐Band Photodetector

“…The responsivities to 238 and 1030 nm wavelengths are 88.5 and 1.24 mA W −1 , respectively. Compared with the reports of β‐Ga 2 O 3 UV photodetectors, the responsivity of the mentioned device is no better than them . This is because the performance of the device is limited by the crystalline quality of the heteroepitaxial β‐Ga 2 O 3 film.…”

“…β‐Ga 2 O 3 with an ultra‐wide bandgap energy at room temperature has been regarded as a promising material for next‐generation power electronic devices and optoelectronic . The 4.9 eV bandgap means that the β‐Ga 2 O 3 ‐based photodetectors can detect the solar‐blind UV band, which can eliminate unnecessary interference with visible wavelength under solar radiation and make it efficient for detecting solar‐blind UV light with weak intensity .…”

The Investigation of Hybrid PEDOT:PSS/β-Ga2O3 Deep Ultraviolet Schottky Barrier Photodetectors

“…The β-Ga 2 O 3 flakes with the thicknesses of 15–25 μm were mechanically exfoliated from the (100) β-Ga 2 O 3 substrate with the electron concentration of 7 × 10 16 cm −3 . For the electron density is 2–3 orders of magnitude higher than that in the unintentionally doped Ga 2 O 3 epilayer deposited on sapphire substrate in [30] and the highly conductive PEDOT:PSS films was used in this paper, so the pn heterojunction was formed in [30] while Schottky junction was formed in this paper [ 30 ]. Figure 1 a shows the schematic diagram of the hybrid PEDOT:PSS/β-Ga 2 O 3 Schottky diode.…”

“…Therefore, less carriers can be captured by the defects in [31], resulting in the shorter rise time and decay time. Furthermore, the overshooting feature can be observed from the shapes of photoresponse curves with a wedgy head at the lower P light of 150 μW/cm 2 than that occurred at the P light of 600 μW/cm 2 in [30] for the effective collection of photogenerated carriers under the reverse bias of − 1.2 V rather than 0 V. Figure 6 depicts the responsivity characteristics versus the illumination optical λ under the V bias of − 1.2 V. The maximum responsivity R max of 0.62 A/W is achieved at a λ of 244 nm and the corresponding external quantum efficiency(EQE) of 3.16 × 10 2 % calculated by the expression EQE = hcR max /(eλ), much higher than that obtained in [30,38] for the effective collection of photogenerated carriers, where R max is the peak responsivity, and h is the Plank constant. e and λ are the electronic charge and the illumination wavelength, respectively.…”

Structural Engineering of Dispersed Graphene Flakes into ZnO Nanotubes on Discontinues Ultra‐Nanocrystalline Diamond Substrates for High‐Performance Photodetector with Excellent UV Light to Dark Current Ratios

“…Besides, the photocurrent increases with time under the UV on/off cycles of ZnTs/UNCD when compared to other devices (such as ZnTs, GrF-ZnTs, and GrF-ZnTs/UNCD). [26][27][28][29][30][31][32][33] In addition, excellent dispersion of GrF on surface of ZnTs potentially contributes to the high photocurrent because well-etched ZnTs surface on UNCD interlayer also enhance light absorption. Figure 8 shows the photoresponsivity curve of ZnTs, GrF-ZnTs, ZnTs-UNCD, and GrF-ZnTs/UNCD, respectively.…”