A 4×4 metal-semiconductor-metal rectangular deep-ultraviolet detector array of Ga<sub>2</sub>O<sub>3</sub> photoconductor with high photo response

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The solar-blind ultraviolet(UV) photodetectors(PDs) with metal-semiconductor-metal(MSM) structure were fabricated based on β-(Al0.25Ga0.75)2O3/β-Ga2O3 film grown by metal-organic chemical vapor deposition(MOCVD).And yet,various surface states increase dark current and a large number of defects can hinder the transport of carriers, resulting in low switching ratio and low responsivity of the device. In this paper,β-(Al0.25Ga0.75)2O3 films are used as surface passivation materials, in addition owning to its wide band gap, excellent light transmission and high lattice matching with β-Ga2O3. We explored the change and mechanism of the detection performance of the β-Ga2O3 detector after β-(Al0.25Ga0.75)2O3 surface passivation. It was found that under the illumination with 254 nm light at 5 V bias, the β-(Al0.25Ga0.75)2O3/β-Ga2O3 PDs showed dark current is just 18 pA and high current on/off ratio is 2.16× 105,the dark current is sharply reduced about 50 times after passivation of the β-Ga2O3 surface, and current on/off ratio increased by approximately 2 times.The results show that β-Ga2O3 detectors with β-(Al0.25Ga0.75)2O3 surface passivation offer superior detector performance.

Section: Resultsmentioning

confidence: 69%

Dramatic reduction in dark current of β-Ga₂O₃ ultraviolet photodectors via β-(Al_0.25Ga_0.75)₂O₃ surface passivation

Yue¹,

Ji²,

Li³

et al. 2023

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“…Meanwhile, Zn x Mg 1−x O tends to undergo phase separation when the relative content of Mg meets the requirement for a wider band gap, and diamond only responds to light with wavelengths shorter than 225 nm. [3,4] Gallium oxide (Ga 2 O 3 ) has five different phases (α, β , γ, ε, and δ ), which endow it with an adjustable band gap in the range of 4.5 eV-5.3 eV, [5][6][7][8][9] precisely corresponding to the response light wavelength range below 280 nm. Among them, the monoclinic Ga 2 O 3 (β -Ga 2 O 3 ) is the most thermodynamically stable phase, with an intrinsic band gap of about 4.8 eV, good mobility (100 cm 2 /(V•s)) and a high breakdown field (8 MV/cm).…”

Section: Introductionmentioning

confidence: 99%

A self-powered ultraviolet photodetector based on a Ga₂O₃/Bi₂WO₆ heterojunction with low noise and stable photoresponse

Yang¹,

Peng²,

Liu³

et al. 2023

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A self-powered solar-blind ultraviolet (UV) photodetector (PD) was successfully constructed on Ga2O3/Bi2WO6 heterojunction, which was fabricated by spin-coating the hydrothermally-grown Bi2WO6 onto MOCVD-grown Ga2O3 film. The results show that a typical type-I heterojunction is formed at the interface of Ga2O3 film and clustered Bi2WO6, which demonstrates a distinct photovoltaic effect with an open-circuit voltage of 0.18 V under the irradiation of 254 nm UV light. Moreover, the Ga2O3/Bi2WO6 PD displays excellent photodetection performance with an ultralow dark current of ~6 fA, and a high light-to-dark current ratio (PDCR) of 3.5×104 in self-powered mode (0 V), as well as a best responsivity of 2.21 mA/W in power supply mode (5 V). Besides, the PD possesses a stable and fast response speed under different light intensities and voltages. At zero voltage, the PD exhibits a fast rise time of 132 ms and 162 ms, as well as a quick decay time of 69 ms and 522 ms, respectively. In general, the newly attempted Ga2O3/Bi2WO6 heterojunction may become a potential candidate for realizing self-powered and high-performance UV photodetectors.

“…Although encountering the difficulties of p-doping and device processing, Ga 2 O 3 unfold its superiority before researchers' eyes around the world in terms of solarblind deep ultraviolet (DUV) photodetectors and high-power devices, owing to its appropriate properties in nature. [3][4][5] The E g of ∼ 4.9 eV allows Ga 2 O 3 to have strong absorbance in the DUV region, thus Ga 2 O 3 is quite suitable for constructing DUV photodetectors. [3,6] Currently, a great deal of researches has been focused on the photodetectors based on semiconducting Ga 2 O 3 materials.…”

Section: Introductionmentioning

confidence: 99%

One ε-Ga₂O₃-based solar-blind Schottky photodetector emphasizing high photocurrent gain and photocurrent-intensity linearity

Gao

et al. 2023

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In this work, the ε-Ga2O3 thin film was grown on sapphire substrate by using metalorganic chemical vapor deposition (MOCVD) method, and then was used to fabricate a deep-ultraviolet (DUV) photodetector (PD). The ε-Ga2O3 thin film shown good crystal quality and decent surface morphology. Irradiated by a 254 nm DUV light, the photodetector displayed good optoelectronic performance and high wavelength selectivity, such as photoresponsivity (R) of 175.69 A/W, detectivity (D *) of 2.46×1015 Jones, external quantum efficiency (EQE) of 8.6×104% and good photocurrent-intensity linearity, suggesting decent DUV photo-sensing performance. At 5 V and under illumination with light intensity of 800 μW/cm2, the photocurrent gain is as high as 859 owing to the recycling gain mechanism and delayed carrier recombination; and the photocurrent gain decrease as the incident light intensity increase because of the recombination of photogenerated carriers by the large photon flux.