Journal articles: 'Ultraviolet Photodetector'

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Xie, Haowei, Chenxu Kang, Muhammad Ahsan Iqbal, Xiaoliang Weng, Kewen Wu, Wei Tang, Lu Qi, and Yu-Jia Zeng. "Ferroelectric Tuning of ZnO Ultraviolet Photodetectors." Nanomaterials 12, no. 19 (September 27, 2022): 3358. http://dx.doi.org/10.3390/nano12193358.

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The ferroelectric field effect transistor (Fe-FET) is considered to be one of the most important low-power and high-performance devices. It is promising to combine a ferroelectric field effect with a photodetector to improve the photodetection performance. This study proposes a strategy for ZnO ultraviolet (UV) photodetectors regulated by a ferroelectric gate. The ZnO nanowire (NW) UV photodetector was tuned by a 2D CuInP2S6 (CIPS) ferroelectric gate, which decreased the dark current and enhanced the responsivity and detectivity to 2.40 × 104 A/W and 7.17 × 1011 Jones, respectively. This strategy was also applied to a ZnO film UV photodetector that was tuned by a P(VDF-TrFE) ferroelectric gate. Lower power consumption and higher performance can be enabled by ferroelectric tuning of ZnO ultraviolet photodetectors, providing new inspiration for the fabrication of high-performance photodetectors.

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Fan, Zelong, Zuoyan Qin, Lei Jin, Yuan Cao, Zhongyu Yue, Baikui Li, Honglei Wu, and Zhenhua Sun. "Aluminum nitride crystal-based photodetector with bias polarity-dependent spectral selectivity." Journal of Vacuum Science & Technology A 41, no. 1 (January 2023): 013204. http://dx.doi.org/10.1116/5.0133162.

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Visible-blind ultraviolet-selective photodetection and ultraviolet-visible broad spectral photodetection are two essential functions eagerly pursued in each application area. However, they usually cannot be realized simultaneously in a bare photodetector because their different underlying photoexcitation processes would interfere with each other. In this work, a photodetector integrating the two distinct photodetector characteristics is presented. The device is prepared based on the heterojunction of a large-scale aluminum nitride bulk crystal and monolayer graphene. The visible-blind ultraviolet-selective photodetection and the ultraviolet-visible broad spectral photodetection are separately manifested in the device depending on the bias polarity. Under a negative bias, the device is a visible-blind deep-ultraviolet photodetector, demonstrating a 193/785 nm rejection ratio of over 106 for the photocurrent and a 193/405 nm rejection ratio of over 103 for the signal/noise ratio. Under a positive bias, the device performs as a broad spectral photodetector responding to light from 193 to 785 nm. Systematical characterization reveals that different photodetection manners are the synergistical results of the different photon energies of the incident light, wavelength-dependent penetration depths in AlN, and the different working modes of the device under different bias conditions. This work provides a particular dual-functional photodetector, which is of great significance in terms of both application and device physics.

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Yan, Xu, Xueqiang Ji, Jinjin Wang, Chao Lu, Zuyong Yan, Shengrun Hu, Sai Zhang, and Peigang Li. "Improve photo-to-dark current ratio of p-Si/SiO₂/n-Ga₂O₃ heterojunction solar-blind photodetector by inserting SiO₂ barrier layer." Journal of Vacuum Science & Technology B 40, no. 5 (September 2022): 052207. http://dx.doi.org/10.1116/5.0107495.

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In this study, the solar-blind ultraviolet photodetectors based on p-Si/Ga2O3 and p-Si/SiO2/n-Ga2O3 heterojunctions were fabricated by metalorganic chemical vapor deposition, respectively. Benefitting from the electron-blocking ability of SiO2 dielectric layer insertion, p-Si/SiO2/n-Ga2O3 photodetectors exhibit a very low dark current of 1.14 × 10−12 A, which is 4 orders of magnitude lower than p-Si/Ga2O3 photodetectors (3.22 × 10−8 A). At the same time, a high photo-to-dark current ratio (1.81 × 105) of p-Si/SiO2/n-Ga2O3 photodetectors was obtained under UV light (λ = 254 nm) at −15 V. Meanwhile, the p-Si/SiO2/n-Ga2O3 devices express better photodetection performance, in which the responsivity and EQE are about two times more than that of p-Si/Ga2O3 photodetectors. Furthermore, the photodetector was found to possess impressive photodetection stabilities. Our results indicate that the p-Si/SiO2/n-Ga2O3 photodetector is an excellent candidate for high-sensitivity, ultrafast response solar-blind UV light detection.

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Wu, Chao, Huaile He, Haizheng Hu, Aiping Liu, Shunli Wang, Daoyou Guo, and Fengmin Wu. "Self-healing wearable self-powered deep ultraviolet photodetectors based on Ga₂O₃." Journal of Semiconductors 44, no. 7 (July 1, 2023): 072807. http://dx.doi.org/10.1088/1674-4926/44/7/072807.

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Abstract Gallium oxide (Ga2O3) based flexible heterojunction type deep ultraviolet (UV) photodetectors show excellent solar-blind photoelectric performance, even when not powered, which makes them ideal for use in intelligent wearable devices. However, traditional flexible photodetectors are prone to damage during use due to poor toughness, which reduces the service life of these devices. Self-healing hydrogels have been demonstrated to have the ability to repair damage and their combination with Ga2O3 could potentially improve the lifetime of the flexible photodetectors while maintaining their performance. Herein, a novel self-healing and self-powered flexible photodetector has been constructed onto the hydrogel substrate, which exhibits an excellent responsivity of 0.24 mA/W under 254 nm UV light at zero bias due to the built-in electric field originating from the PEDOT: PSS/Ga2O3 heterojunction. The self-healing of the Ga2O3 based photodetector was enabled by the reversible property of the synthesis of agarose and polyvinyl alcohol double network, which allows the photodetector to recover its original configuration and function after damage. After self-healing, the photocurrent of the photodetector decreases from 1.23 to 1.21 μA, while the dark current rises from 0.95 to 0.97 μA, with a barely unchanged of photoresponse speed. Such a remarkable recovery capability and the photodetector’s superior photoelectric performance not only significantly enhance a device lifespan but also present new possibilities to develop wearable and intelligent electronics in the future.

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Liu, Geng, Liang Yao, Ying Liu, Rongdun Hong, Ruijun Zhang, and Feng Zhang. "Study on SiC UV/EUV Coaxial Photodetector." Journal of Physics: Conference Series 2549, no. 1 (July 1, 2023): 012014. http://dx.doi.org/10.1088/1742-6596/2549/1/012014.

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Abstract In this paper, a novel 4H-SiC coaxial p-i-n ultraviolet photodetector with intense photon absorption and high quantum efficiency is studied. The spectral response and electric field distribution of the detector are calculated by TCAD software. The results showed that the innovative 4H-SiC ultraviolet coaxial p-i-n photodetector has a spectral response peak of 0.1998 A/W at 260 nm illumination wavelength and has more than twice response higher than the traditional 4H-SiC p-i-n photodetector, when the illumination wavelength is under 270 nm. The quantum efficiency of the coaxial photodetector reaches 95.3%. Moreover, in the wavelength range of EUV, the 4H-SiC ultraviolet coaxial photodetector shows a relatively high response, while the response is barely observed for the traditional 4H-SiC p-i-n photodetector. For the large area coaxial p-i-n photodetector, the problem of laterally undepleted i layer can be solved by multiple P+-type implanation. The new structure significantly enhances the rate of incident light absorption, prevents the light absorption of the conventional metal electrode and P+ layer, and provides an innovative approach for the construction of ultraviolet photodetectors in the future.

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Kaawash, N. M. S., D. I. Halge, V. N. Narwade, J. W. Dadge, and K. A. Bogle. "Fabrication of Near Ultraviolet Photodetector using α-Fe₂O₃ Thin FilmSynthesized via Spray Coating Technique." Journal of Physics: Conference Series 2426, no. 1 (February 1, 2023): 012011. http://dx.doi.org/10.1088/1742-6596/2426/1/012011.

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Abstract A UV photodetector was created using a spray-deposited α-Fe2O3 thin film on a glass substrate at 160 °C. The film’s thickness was approximately 110 nm. With a near UV light at a wavelength of 340 nm and an intensity of 140 µW/cm2, the photosensitivity of an individual α-Fe2O3 thin film photodetector was greater than 40%. An individual α-Fe2O3 thin film-based photodetector’s rapid photoresponse time of 1.6 ms and responsivity of ~ 1 mA/W can be attributed to the band gap and chemisorption of oxygen on the film’s surface. The photodetectors’ simple, low-cost, and large-scale fabrication demonstrates the fabrication of a stable, reversible, and rapid photo-responsive photodetector for near UV wavelength.

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Grahn, Holger T. "Nonpolar-Oriented GaN Films for Polarization-Sensitive and Narrow-Band Photodetectors." MRS Bulletin 34, no. 5 (May 2009): 341–47. http://dx.doi.org/10.1557/mrs2009.97.

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AbstractThis article reviews the optical polarization properties of unstrained and strained GaN films with a nonpolar orientation. In unstrained a -plane GaN films, the A exciton becomes completely linearly polarized perpendicular to the c-axis, whereas the B and C excitons are only partially polarized. In m -plane or a -plane GaN films under anisotropic in-plane compressive strain, all three interband transitions between the three uppermost valence bands and the conduction band can become linearly polarized for sufficiently large strain values. The complete linear polarization can be directly observed in reflection, transmission, or photoreflectance by a polarization-dependent energy gap. This complete linear polarization can be used to realize polarization-sensitive photodetectors in the ultraviolet spectral range, which do not need a polarization filter in front of the photodetector. By combining a polarization filter and photodetector or two photodetectors from the same material with their c-axes oriented perpendicular to each other, a narrowband photodetection configuration can be achieved in the ultraviolet spectral range with a band width below 8 nm. Since both realizations are also polarization sensitive, a configuration with four photodetectors is necessary to achieve narrow-band sensitivity regardless of the polarization state of the incident light. At the same time, the configuration with four photodetectors allows for the determination of the absolute angle of polarization.

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Zhou, Guigang, Huancheng Zhao, Xiangyang Li, Zhenhua Sun, Honglei Wu, Ling Li, Hua An, Shuangchen Ruan, and Zhengchun Peng. "Highly-Responsive Broadband Photodetector Based on Graphene-PTAA-SnS2 Hybrid." Nanomaterials 12, no. 3 (January 29, 2022): 475. http://dx.doi.org/10.3390/nano12030475.

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The development of wearable systems stimulate the exploration of flexible broadband photodetectors with high responsivity and stability. In this paper, we propose a facile liquid-exfoliating method to prepare SnS2 nanosheets with high-quality crystalline structure and optoelectronic properties. A flexible photodetector is fabricated using the SnS2 nanosheets with graphene-poly[bis(4-phenyl) (2,4,6-trimethylphenyl) amine (PTAA) hybrid structure. The liquid-exfoliated SnS2 nanosheets enable the photodetection from ultraviolet to near infrared with high responsivity and detectivity. The flexible broadband photodetector demonstrates a maximum responsivity of 1 × 105 A/W, 3.9 × 104 A/W, 8.6 × 102 A/W and 18.4 A/W under 360 nm, 405 nm, 532 nm, and 785 nm illuminations, with specific detectivity up to ~1012 Jones, ~1011 Jones, ~109 Jones, and ~108 Jones, respectively. Furthermore, the flexible photodetector exhibits nearly invariable performance over 3000 bending cycles, rendering great potentials for wearable applications.

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You, Jie, Yichi Zhang, Maolong Yang, Bo Wang, Huiyong Hu, Zimu Wang, Jinze Li, Hao Sun, and Liming Wang. "Ultraviolet-Visible-Near Infrared Broadband Photodetector Based on Electronspun Disorder ZnO Nanowires/Ge Quantum Dots Hybrid Structure." Crystals 12, no. 2 (January 25, 2022): 172. http://dx.doi.org/10.3390/cryst12020172.

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Ultraviolet-visible-near infrared broadband photodetectors have significant prospects in many fields such as image sensing, communication, chemical sensing, and day and nighttime surveillance. Hybrid one-dimensional (1D) and zero-dimensional (0D) materials are attractive for broadband-responsive photodetectors since its unique charges transfer characteristics and facile fabrication processes. Herein, a Si/ZnO nanowires/Ge quantum dots photodetector has been constructed via processes that combined electrospinning and spin-coating methods. A broadband response behavior from ultraviolet to near-infrared (from 250 to 1550 nm) is observed. The responsivity of the hybrid structure increases around three times from 550 to 1100 nm compared with the pure Si photodetector. Moreover, when the photodetector is illuminated by a light source exceeding 1100 nm, such as 1310 and 1550 nm, there is also a significant photoresponse. Additionally, the ZnO NWs/Ge quantum dots heterostructure is expected to be used in flexible substrates, which benefits from electrospinning and spin-coating processes. The strategy that combines 1D ZnO NWs and 0D solution-processed Ge QDs nanostructures may open a new avenue for flexible and broadband photodetector.

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Fong, Chee Yong, Sha Shiong Ng, NurFahana Mohd Amin, Fong Kwong Yam, and Zainuriah Hassan. "Sol-gel-derived gallium nitride thin films for ultraviolet photodetection." Microelectronics International 36, no. 1 (January 7, 2019): 8–13. http://dx.doi.org/10.1108/mi-12-2017-0074.

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Purpose This study aims to explore the applicability of the sol-gel-derived GaN thin films for UV photodetection. Design/methodology/approach GaN-based ultraviolet (UV) photodetector with Pt Schottky contacts was fabricated and its applicability was investigated. The current-voltage (I-V) characteristics of the GaN-based UV photodetector under the dark current and photocurrent were measured. Findings The ideality factors of GaN-based UV photodetector under dark current and photocurrent were 6.93 and 5.62, respectively. While the Schottky barrier heights (SBH) for GaN-based UV photodetector under dark current and photocurrent were 0.35 eV and 0.34 eV, respectively. The contrast ratio and responsivity of this UV photodetector measured at 5 V were found to be 1.36 and 1.68 μA/W, respectively. The photoresponse as a function of time was measured by switching the UV light on and off continuously at different forward biases of 1, 3 and 6 V. The results showed that the fabricated UV photodetector has reasonable stability and repeatability. Originality/value This work demonstrated that GaN-based UV photodetector can be fabricated by using the GaN thin film grown by low-cost and simple sol-gel spin coating method.

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Zhang, Xiang Yu, Dongbo Wang, Zhi Zeng, Chenchen Zhao, Yaxin Liu, Bingke Zhang, Jingwen Pan, Donghao Liu, and Jinzhong Wang. "PVP-Assisted Hydrothermal Synthesis of Bi2O2Se Nanosheets for Self-Powered Photodetector." Journal of Solar Energy Research Updates 9 (February 28, 2022): 1–8. http://dx.doi.org/10.31875/2410-2199.2022.09.01.

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Abstract: Bi2O2Se nanosheets were successfully synthesized via a facile one-step PVP-assisted hydrothermal process for the first time. Corresponding characterizations, such as XRD, XPS, SEM and TEM, were carried out to investigate the formation of the products on the amount of PVP in the reaction system. Results revealed that the single-crystalline Bi2O2Se nanosheets with small mean lateral size of 176.3 nm were obtained when the amount of PVP is 0.75 g. Single-crystalline Bi2O2Se nanosheets self-powered photodetector exhibited excellent photodetection performance, superior to that of self-powered photodetectors based on the products synthesized without PVP and other nanomaterials. Under the illumination of 365 nm ultraviolet light, the rise time, responsivity and detectivity could approach up to 9 ms, 14.24 mA/W and 3.16×108 Jones, respectively. Bi2O2Se devices have high photoresponse even in the visible and near infrared bands due to its suitable band gap. The present work provides a novel preparation route of Bi2O2Se via hydrothermal method and PVP assisted synthesis of Bi2O2Se nanosheets is reported for the first time. Bi2O2Se nanosheets self-powered photodetector exhibited excellent photodetection performance and points out a direction for the evolution of self-powered photodetectors in the in the future.

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Zhu, Mengru, Zhiwei Zhao, Yong Fang, Zhengjin Weng, and Wei Lei. "A Flexible Solar-blind Ultraviolet Photodetector based on Carbon Nanodots." Journal of Physics: Conference Series 2065, no. 1 (November 1, 2021): 012016. http://dx.doi.org/10.1088/1742-6596/2065/1/012016.

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Abstract A flexible solar-blind ultraviolet (UV) photodetector based on the carbon nanodots (CNDs) was fabricated on a polyethylene terephthalate (PET) substrate. The responsivity of 1.2 mA/W is obtained for 10 V applied bias under 254 nm illumination. Further, bending tests were carried out under the 0.2% strain, and the results showed that this flexible photodetector had stable characteristics and no obviously decrease of the photocurrent. The bending performances exhibit excellent potential for the fabrication of smart and flexible photodetectors.

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Zhou, Shuren, Qiqi Zheng, Chenxi Yu, Zhiheng Huang, Lingrui Chen, Hong Zhang, Honglin Li, et al. "A High-Performance ε-Ga2O3-Based Deep-Ultraviolet Photodetector Array for Solar-Blind Imaging." Materials 16, no. 1 (December 28, 2022): 295. http://dx.doi.org/10.3390/ma16010295.

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One of the most important applications of photodetectors is as sensing units in imaging systems. In practical applications, a photodetector array with high uniformity and high performance is an indispensable part of the imaging system. Herein, a photodetector array (5 × 4) consisting of 20 photodetector units, in which the photosensitive layer involves preprocessing commercial ε-Ga2O3 films with high temperature annealing, have been constructed by low-cost magnetron sputtering and mask processes. The ε-Ga2O3 ultraviolet photodetector unit shows excellent responsivity and detectivity of 6.18 A/W and 5 × 1013 Jones, respectively, an ultra-high light-to-dark ratio of 1.45 × 105, and a fast photoresponse speed (0.14/0.09 s). At the same time, the device also shows good solar-blind characteristics and stability. Based on this, we demonstrate an ε-Ga2O3-thin-film-based solar-blind ultraviolet detector array with high uniformity and high performance for solar-blind imaging in optoelectronic integration applications.

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Teker, Kasif. "Dielectrophoretic Assembly of Aluminum Nitride (AlN) Single Nanowire Deep Ultraviolet Photodetector." Journal of Nano Research 60 (November 2019): 86–93. http://dx.doi.org/10.4028/www.scientific.net/jnanor.60.86.

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High UV-light sensitivity, fast response, and low power consumption are the most important features of nanowire-based devices for new applications in photodetectors, optical switches, and image sensors. Single AlN nanowire deep ultraviolet (UV) photodetector has been fabricated utilizing very high-quality AlN nanowires through a very practical dielectrophoretic assembly scheme. The low-voltage (≤ 3 V) operating UV photodetector has selectively shown a high photocurrent response to the 254 nm UV light. Furthermore, the photocurrent transients have been modelled to determine the rise and decay time constants as 7.7 s and 11.5 s, respectively. In consequence, combination of deep UV light selectivity and low voltage operation make AlN nanowires great candidates for the development of compact deep UV photodetectors.

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Liu, Zhiyi, Xiaomei Hu, and Mingsheng Long. "High-performances ultraviolet photodetector based on vertical van der Waals heterostructures." Journal of Physics: Conference Series 2383, no. 1 (December 1, 2022): 012037. http://dx.doi.org/10.1088/1742-6596/2383/1/012037.

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High-performance ultraviolet (UV) photodetectors play a very important role in many fields, especially in the military, biomedical and other fields. [1]In recent years, many studies have realized ultraviolet photodetectors of 2D layered materials, overcome the problems of traditional ultraviolet detectors that are large and use high voltages. [1]Up to now, most of these works use atomically thin layers and simple p-n van der Waals (vdW) heterostructures, which have difficulty meeting the conditions of high sensitivity and ultrafast response at the same time. we report the double p-n van der Waals (vdW) heterostructure built on a large electrode. The two p-n junctions connected in parallel were proven to be able to effectively separate photo-generated carriers and suitable for ultraviolet light. This new type of photodetector exhibits competitive performance, including high R up to 254.8 A/W under UV light, and fast photoresponse τr = 7.9 μs and τd = 3.9 μs. These results provide an ideal platform for realizing highly sensitive UV photodetectors.

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Ye, Qiannan, Xu Zhang, Rihui Yao, Dongxiang Luo, Xianzhe Liu, Wenxin Zou, Chenxiao Guo, Zhuohui Xu, Honglong Ning, and Junbiao Peng. "Research and Progress of Transparent, Flexible Tin Oxide Ultraviolet Photodetector." Crystals 11, no. 12 (November 28, 2021): 1479. http://dx.doi.org/10.3390/cryst11121479.

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Optical detection is of great significance in various fields such as industry, military, and medical treatment, especially ultraviolet (UV) photodetectors. Moreover, as the demand for wearable devices continues to increase, the UV photodetector, which is one of the most important sensors, has put forward higher requirements for bending resistance, durability, and transparency. Tin oxide (SnO2) has a wide band gap, high ultraviolet exciton gain, etc., and is considered to be an ideal material for preparing UV photodetectors. At present, SnO2-based UV photodetectors have a transparency of more than 70% in the visible light region and also have excellent flexibility of 160% tensile strain. Focusing on SnO2 nanostructures, the article mainly summarizes the progress of SnO2 UV photodetectors in flexibility and transparency in recent years and proposes feasible optimization directions and difficulties.

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Yuan, Dingcheng, Lingyu Wan, Haiming Zhang, Jiang Jiang, Boxun Liu, Yongsheng Li, Zihan Su, and Junyi Zhai. "An Internal-Electrostatic-Field-Boosted Self-Powered Ultraviolet Photodetector." Nanomaterials 12, no. 18 (September 15, 2022): 3200. http://dx.doi.org/10.3390/nano12183200.

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Self-powered photodetectors are of significance for the development of low-energy-consumption and environment-friendly Internet of Things. The performance of semiconductor-based self-powered photodetectors is limited by the low quality of junctions. Here, a novel strategy was proposed for developing high-performance self-powered photodetectors with boosted electrostatic potential. The proposed self-powered ultraviolet (UV) photodetector consisted of an indium tin oxide and titanium dioxide (ITO/TiO2) heterojunction and an electret film (poly tetra fluoroethylene, PTFE). The PTFE layer introduces a built-in electrostatic field to highly enhance the photovoltaic effect, and its high internal resistance greatly reduces the dark current, and thus remarkable performances were achieved. The self-powered UV photodetector with PTFE demonstrated an extremely high on–off ratio of 2.49 × 105, a responsivity of 76.87 mA/W, a response rise time of 7.44 ms, and a decay time of 3.75 ms. Furthermore, the device exhibited exceptional stability from room temperature to 70 °C. Compared with the conventional ITO/TiO2 heterojunction without the PTFE layer, the photoresponse of the detector improved by 442-fold, and the light–dark ratio was increased by 8.40 × 105 times. In addition, the detector is simple, easy to fabricate, and low cost. Therefore, it can be used on a large scale. The electrostatic modulation effect is universal for various types of semiconductor junctions and is expected to inspire more innovative applications in optoelectronic and microelectronic devices.

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Lu, Xiao-ling, Xiao-bin Guo, Feng-chao Su, Zheng Su, Wen-hai Qiu, Yan-ping Jiang, Wen-hua Li, Zhen-hua Tang, and Xin-gui Tang. "High-performance Al-doped ZnO flexible ultraviolet photodetector via piezo-phototronic effect." Journal of Applied Physics 133, no. 7 (February 21, 2023): 075301. http://dx.doi.org/10.1063/5.0133534.

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Al-doped ZnO (AZO) flexible ultraviolet (UV) photodetectors were fabricated on polyethylene terephthalate substrates by radio frequency magnetron sputtering technique at room temperature. The single-layer AZO photodetector has a high photocurrent/dark current ratio and exhibits excellent photoresponse performance under UV illumination. When the tensile strain increases from 0 to 0.33, the photocurrent gradually increases, and the sensitivity and linear dynamic range increase by 10 times and 1.5 times, respectively. Under 23.5 mW/cm2 UV illumination at 4 V bias, the rise time and fall time are 0.2 and 0.3 s, respectively, showing that the AZO flexible UV photodetector has good reproducibility and stability. The energy band diagrams before and after applying tensile strain are analyzed to further study the interface modulation behavior. The results reveal that the piezo-phototronic effect has an important influence on the performance optimization and modulation of flexible UV photodetectors.

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SHING, CHRISTOPHER, LIQIAO QIN, and SHALYA SAWYER. "BIO-SENSING SENSITIVITY OF A NANOPARTICLE BASED ULTRAVIOLET PHOTODETECTOR." International Journal of High Speed Electronics and Systems 20, no. 03 (September 2011): 505–13. http://dx.doi.org/10.1142/s0129156411006799.

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Bio-sensing sensitivity of a spectrally selective nanoparticle based ultraviolet (UV) photodetector is characterized in comparison to a silicon photodiode and a photomultiplier tube (PMT). The nanoparticle based photodetector is comprised of poly-vinyl alcohol (PVA) coated zinc-oxide ( ZnO ) nanoparticles deposited on an aluminum-gallium-nitride ( AlGaN ) epitaxially grown substrate. The sensitivity was determined by measuring the fluorescence intensity of the native fluorophore, tryptophan, in Escherichia coli (E-coli, ATCC-25922) cells. Tryptophan intrinsically fluoresces with a peak at 340 nm under 280 nm UV light illumination. It is shown that this detector can sense the concentration of E-coli to 2.5 × 108 cfu/mL while the silicon photodiode cannot detect the intrinsic fluorescence at all. Nevertheless, the PMT outperformed the ZnO nanoparticle- AlGaN substrate based photodetector with the ability to sense E-coli concentrations to 3.91 × 106 cfu/mL. However, because PMT based systems are commonly limited by high dark current, susceptible to environmental changes, sensitive to ambient light, are not spectrally selective and have high power consumption, biological detection systems comprised of these ZnO nanoparticle- AlGaN substrate based photodetectors can be more effective for near real time characterization of potential bacterial contamination.

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Shang, Guoxin, Libin Tang, Gang Wu, Shouzhang Yuan, Menghan Jia, Xiaopeng Guo, Xin Zheng, Wei Wang, Biao Yue, and Kar Seng Teng. "High-Performance NiO/TiO2/ZnO Photovoltaic UV Detector." Sensors 23, no. 5 (March 2, 2023): 2741. http://dx.doi.org/10.3390/s23052741.

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The ultraviolet (UV) photodetector has found many applications, ranging from optical communication to environmental monitoring. There has been much research interest in the development of metal oxide-based UV photodetectors. In this work, a nano-interlayer was introduced in a metal oxide-based heterojunction UV photodetector to enhance the rectification characteristics and therefore the device performance. The device, which consists of nickel oxide (NiO) and zinc oxide (ZnO) sandwiching an ultrathin dielectric layer of titanium dioxide (TiO2), was prepared by radio frequency magnetron sputtering (RFMS). After annealing, the NiO/TiO2/ZnO UV photodetector exhibited a rectification ratio of 104 under UV irradiation of 365 nm at zero bias. The device also demonstrated a high responsivity of 291 A/W and a detectivity of 6.9 × 1011 Jones at +2 V bias. Such a device structure provides a promising future for metal oxide-based heterojunction UV photodetectors in a wide range of applications.

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Huang, Zhiheng, Shuren Zhou, Lingrui Chen, Qiqi Zheng, Honglin Li, Yuanqiang Xiong, Lijuan Ye, et al. "Fully Transparent Amorphous Ga2O3-Based Solar-Blind Ultraviolet Photodetector with Graphitic Carbon Electrodes." Crystals 12, no. 10 (October 9, 2022): 1427. http://dx.doi.org/10.3390/cryst12101427.

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In recent years, transparent electrode materials have had a positive effect on improving the responsivity of photodetectors by increasing the effective illumination area of devices due to their high transmittance. In this work, by using radio frequency magnetron sputtering and simple mask technology, an amorphous Ga2O3-based solar-blind UV photodetector with graphitic carbon (C) electrodes was created. The device exhibits a high responsivity of 16.34 A/W, an external quantum efficiency of 7979%, and excellent detectivity of 1.19 × 1013 Jones at room temperature under a light density of 5 μw/cm2. It has been proved that C electrodes can replace the traditional noble metal electrode. Additionally, the potential of the transparent photodetector array in solar-blind imaging is explored. We believe that the present study will pave the way for the preparation of a fully transparent and high-response solar-blind ultraviolet photodetector array.

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Rogalski, Antoni, Zbigniew Bielecki, Janusz Mikołajczyk, and Jacek Wojtas. "Ultraviolet Photodetectors: From Photocathodes to Low-Dimensional Solids." Sensors 23, no. 9 (May 2, 2023): 4452. http://dx.doi.org/10.3390/s23094452.

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The paper presents the long-term evolution and recent development of ultraviolet photodetectors. First, the general theory of ultraviolet (UV) photodetectors is briefly described. Then the different types of detectors are presented, starting with the older photoemission detectors through photomultipliers and image intensifiers. More attention is paid to silicon and different types of wide band gap semiconductor photodetectors such as AlGaN, SiC-based, and diamond detectors. Additionally, Ga2O3 is considered a promising material for solar-blind photodetectors due to its excellent electrical properties and a large bandgap energy. The last part of the paper deals with new UV photodetector concepts inspired by new device architectures based on low-dimensional solid materials. It is shown that the evolution of the architecture has shifted device performance toward higher sensitivity, higher frequency response, lower noise, and higher gain-bandwidth products.

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Li, Shasha, Tao Deng, Yang Zhang, Yuning Li, Weijie Yin, Qi Chen, and Zewen Liu. "Solar-blind ultraviolet detection based on TiO2 nanoparticles decorated graphene field-effect transistors." Nanophotonics 8, no. 5 (April 26, 2019): 899–908. http://dx.doi.org/10.1515/nanoph-2019-0060.

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AbstractSensitive solar-blind ultraviolet (UV) photodetectors are important to various military and civilian applications, such as flame sensors, missile interception, biological analysis, and UV radiation monitoring below the ozone hole. In this paper, a solar-blind UV photodetector based on a buried-gate graphene field-effect transistor (GFET) decorated with titanium dioxide (TiO2) nanoparticles (NPs) was demonstrated. Under the illumination of a 325-nm laser (spot size ~2 μm) with a total power of 0.35 μW, a photoresponsivity as high as 118.3 A/W was obtained, at the conditions of zero gate bias and a source-drain bias voltage of 0.2 V. This photoresponsivity is over 600 times higher than that of a recently reported solar-blind UV photodetector based on graphene/vertical Ga2O3 nanowire array heterojunction (0.185 A/W). Experiments showed that the photoresponsivity of the TiO2 NPs decorated GFET photodetectors can be further enhanced by increasing the source-drain bias voltage or properly tuning the gate bias voltage. Furthermore, the photoresponse time of the TiO2 NPs decorated GFET photodetectors can also be tuned by the source-drain bias and gate bias. This study paves a simple and feasible way to fabricate highly sensitive, cost-efficient, and integrable solar-blind UV photodetectors.

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Zhang, Xiao-Mei, Sian-Hong Tseng, and Ming-Yen Lu. "Large-Area Ultraviolet Photodetectors Based on p-Type Multilayer MoS2 Enabled by Plasma Doping." Applied Sciences 9, no. 6 (March 15, 2019): 1110. http://dx.doi.org/10.3390/app9061110.

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Two-dimensional (2D) MoS2 has recently become of interest for applications in broad range photodetection due to their tunable bandgap. In order to develop 2D MoS2 photodetectors with ultrafast response and high responsivity, up-scalable techniques for realizing controlled p-type doping in MoS2 is necessary. In this paper, we demonstrate a p-type multilayer MoS2 photodetector with selective-area doping using CHF3 plasma treatment. Microscopic and spectroscopic characterization techniques, including atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), are used to investigate the morphological and electrical modification of the p-type doped MoS2 surface after CHF3 plasma treatment. Back-gated p-type MoS2 field-effect transistors (FETs) are fabricated with an on/off current ratio in the order of 103 and a field-effect mobility of 65.2 cm2V−1s−1. They exhibit gate-modulated ultraviolet photodetection with a rapid response time of 37 ms. This study provides a promising approach for the development of mild plasma-doped MoS2 as a 2D material in post-silicon electronic and optoelectronic device applications.

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Syu, Jhih-Chun, Ming-Hung Hsu, Sheng-Po Chang, Shoou-Jinn Chang, and Lucent Lu. "Effect of Oxygen Vacancy Ratio on a GaZTO Solar-Blind Photodetector." Coatings 8, no. 9 (August 21, 2018): 293. http://dx.doi.org/10.3390/coatings8090293.

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A gallium-zinc-tin-oxide (GaZTO) solar-blind photodetector was fabricated via radio frequency sputtering. The transmittance of the GaZTO thin film was >80% in the visible light region, and its energy bandgap ranged from 4.11 to 4.23 eV. Manipulating the oxygen flows changed the ratio of oxygen vacancies, which was confirmed by X-ray photoelectron spectroscopy. The ratio of oxygen vacancies in the GaZTO thin films impacted the performance of the photodetectors. The photocurrent, responsivity, and ultraviolet–visible rejection ratio of the GaZTO solar-blind photodetector were 1.23 × 10−6 A, 9.12 × 10−2 A/W, and 3.48 × 104, respectively, at a 10 V bias under 280 nm light illumination. The transient responses of the synthesized photodetectors were measured and discussed.

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Li, Ying, Zhifeng Shi, Wenqing Liang, Lintao Wang, Sen Li, Fei Zhang, Zhuangzhuang Ma, et al. "Highly stable and spectrum-selective ultraviolet photodetectors based on lead-free copper-based perovskites." Materials Horizons 7, no. 2 (2020): 530–40. http://dx.doi.org/10.1039/c9mh01371g.

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Cheng, Lu, Yanlin Wu, Wei Cai, and Wei Zheng. "Diamond immersion photodetector for 213 nm deep-ultraviolet photodetection." Materials Today Physics 36 (August 2023): 101164. http://dx.doi.org/10.1016/j.mtphys.2023.101164.

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Thompson, Jesse E., Darian Smalley, and Masahiro Ishigami. "Solar-Blind Ultraviolet Photodetectors Based on Vertical Graphene-Hexagonal Boron Nitride Heterostructures." MRS Advances 5, no. 37-38 (2020): 1993–2002. http://dx.doi.org/10.1557/adv.2020.331.

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AbstractPhotodetectors operating in the ultraviolet (UV) play a pivotal role in applications such as ozone monitoring and biosensing. One key factor to successfully implementing such photodetectors is that they must be solar-blind to avoid detecting ambient visible and infrared light. Unfortunately, UV photodetectors based on silicon and other typical semiconductors are not natively solar-blind, since their band gap energies are in the visible range. Hexagonal boron nitride (h-BN) is an example of a wide band gap semiconductor which shows promise for use as the absorbing medium in a UV photodetector device, since its band gap is wide enough to make it inherently insensitive to light in the visible range and above. Here we report on the fabrication and characterization of a graphene-h-BN-heterostructure photodetector which utilizes a vertical geometry, in principle allowing for highly scalable production. We find that our device shows a finite photoresponse to illumination by a 254 nm light source, but not to a 365 nm source, thus suggesting that our device is solar-blind.

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JX, Guo. "Graphene-Quantum Dots Hybrid Based Dual Band Photodetector." Physical Science & Biophysics Journal 7, no. 1 (January 5, 2023): 1–4. http://dx.doi.org/10.23880/psbj-16000234.

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Graphene, which can detect a broad spectrum from ultraviolet to terahertz, is a promising photodetector material because it offers a broad spectral bandwidth and fast response times. However, the nature of weak light absorption has limited the responsivity of graphene-based photodetectors. Here, we demonstrate a responsivity of up to ∼6.7×103 A/W in a hybrid photodetector that consists of monolayer or bilayer graphene covered with a thin film of colloidal quantum dots. At the same time, benefits from gate-tunability, the device can response from the short-wavelength infrared to the visible, and compatibility with current circuit technologies.

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Masuzawa, T., I. Saito, M. Onishi, T. Ebisudani, A. T. T. Koh, D. H. C. Chua, T. Yamada, et al. "High sensitivity photodetector made of amorphous selenium and diamond cold cathode." Canadian Journal of Physics 92, no. 7/8 (July 2014): 667–70. http://dx.doi.org/10.1139/cjp-2013-0648.

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In the present study, high-sensitivity photodetection has been demonstrated using an amorphous selenium (a-Se) based photodetector driven by nitrogen-doped diamond cold cathode. The emission current – applied voltage characteristics are compared between different lighting conditions, and their sensitivities are evaluated in terms of nominal quantum efficiency. The estimated nominal quantum efficiency was 10–40 for visible and up to 1000 for ultraviolet, proving a successful photodetection utilizing carrier multiplication in a-Se.

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Ren, Bing, Meiyong Liao, Masatomo Sumiya, Jian Huang, Linjun Wang, Yasuo Koide, and Liwen Sang. "Vertical-Type Ni/GaN UV Photodetectors Fabricated on Free-Standing GaN Substrates." Applied Sciences 9, no. 14 (July 19, 2019): 2895. http://dx.doi.org/10.3390/app9142895.

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The authors report on a vertical-type visible-blind ultraviolet (UV) Schottky-type photodetector fabricated on a homoepitaxial GaN layer grown on free-standing GaN substrates with a semi-transparent Ni Schottky contact. Owing to the high-quality GaN drift layer with low-density threading dislocation and high electron mobility, the UV photodetector shows a high specific detectivity of more than 1012 Jones and a UV/visible discrimination ratio of ~1530 at −5 V. The photodetector also shows the excellent self-powered photo-response and a high signal-to-noise ratio of more than 104 at zero voltage. It is found that a relatively lower growth rate for the GaN epilayer is preferred to improve the performance of the Schottky-type photodetectors due to the better microstructure and surface properties.

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32

Guo, Yue, Weidong Song, Qing Liu, Yiming Sun, Zhao Chen, Xin He, Qingguang Zeng, Xingjun Luo, Ruiqing Zhang, and Shuti Li. "A porous GaN/MoO₃ heterojunction for filter-free, ultra-narrowband ultraviolet photodetection." Journal of Materials Chemistry C 10, no. 13 (2022): 5116–23. http://dx.doi.org/10.1039/d1tc05992k.

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A porous GaN/MoO3 heterojunction ultraviolet photodetector with visible-blind, filter-free and ultra-narrowband (FWHM <10 nm) response is presented. This narrowband ultraviolet photodetector is promising for secure communication applications.

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Li, Haixia, Bingyi Liu, Weiwei Lin, Yang Liu, Yu Wang, Zhongyuan Zhang, Lun Xiong, and Jiayou Tao. "Enhancing Performance of Broadband Photodetectors Based on Perovskite CsPbBr₃ Nanocrystals/ZnO-Microwires Heterostructures." Science of Advanced Materials 13, no. 9 (September 1, 2021): 1748–55. http://dx.doi.org/10.1166/sam.2021.4072.

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A broadband photodetector response in the ultraviolet (UV)-to-green range (up to 530 nm) based on perovskite CsPbBr3 nanocrystals (NCs)/ZnO-microwires (MWs) heterostructures was realized via a convenient spin-coating method. Under UV light (365 nm) illumination, compared with a bare-ZnO-MW-based photodetector, the CsPbBr3-NCs/ZnO-MWs-heterostructure-based photodetector exhibited a faster photoresponse (<0.1 s) and higher current responsivity (93.50 AW−1), external quantum efficiency (3399%), and detectivity (4.4 × 1010). In addition, the photodetector based on CsPbBr3-NCs/ZnO-MWs heterostructures also exhibited a very fast photoresponse to green light (530 nm). These can be ascribed to the strong light-trapping ability of CsPbBr3 NCs and high charge-transfer efficiency at the CsPbBr3-NCs/ZnO-MWs-heterojunction interface due to the built-in field, which facilitates the spatial separation of the photogenerated carriers. Therefore, this work will develop perovskite/ZnO nanomaterials as promising building blocks for broadband photodetectors and wider optoelectronic applications.

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Shao, Dali, Mingpeng Yu, Jie Lian, and Shayla Sawyer. "Ultraviolet Photodetector Fabricated from 3D WO3 Nanowires/Reduced Graphene Oxide Composite Material." MRS Proceedings 1659 (2014): 193–98. http://dx.doi.org/10.1557/opl.2014.211.

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ABSTRACTAn Ultraviolet (UV) photodetector with high responsivity and relative fast response speed was fabricated from three dimensional WO3 nanowires/reduced graphene oxide (3D WO3 NWs/RGO) composite materials. The 3D WO3 NDs/GN composite was synthesized using a facile three-step synthesis. First, the Na2WO4/Graphene Oxide (GO) precursor was synthesized by homogeneous precipitation. Second, the Na2WO4/GO precursor was transformed into H2WO4/GO composites by acidification. Finally, the H2WO4/GO composites were reduced to 3D WO3 NWs/RGO via hydrothermal reduction process. A maximum photoresponsivity of 4.2 A/W at 374 nm was observed under 20 V bias. The UV photodetector showed relative fast transient response, which is at least 2 orders of magnitude faster than UV photodetectors fabricated from WO3 nanowires. The good photoresponsivity and fast transient response are attributed to improved carrier transport and collection efficiency through graphene.

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Doğan, Ümit, Fahrettin Sarcan, Kamuran Kara Koç, Furkan Kuruoğlu, and Ayşe Erol. "Effects of annealing temperature on a ZnO thin film-based ultraviolet photodetector." Physica Scripta 97, no. 1 (January 1, 2022): 015803. http://dx.doi.org/10.1088/1402-4896/ac4634.

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Abstract In this paper, the effects of annealing temperature on the performance of a ZnO thin film-based Metal-Semiconductor-Metal (MSM) type ultraviolet (UV) photodetector is reported. ZnO thin films were grown on a glass substrate using the Pulsed Filtered Cathodic Vacuum Arc Deposition (PFCVAD) technique at room temperature and after the deposition process the samples were annealed at 400, 450 and 550 °C in air condition to investigate the annealing effect on the structural, electrical, and optical properties of the photodetector. ZnO thin films which have grains in nanometer range has an increasing in the diameter of grains from 10.5 to 18.3 nm as a function of annealing temperature results in a red shift in the cut-off wavelength of the photodetector from 3.25 eV (381 nm) to 3.23 eV (383 nm). It is demonstrated that the sensitivity and the speed (rise/fall times) of the ZnO thin film based MSM photodetectors enhances with increasing post growth annealing temperature of ZnO thin film due to the increase in the absorption coefficient and the decrease of the total area of the grain boundaries due to the larger grain sizes formation in ZnO thin films with increasing thermal annealing temperature.

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Lin, Sheng, Tingjun Lin, Wenliang Wang, Chao Liu, and Yao Ding. "High Performance GaN-Based Ultraviolet Photodetector via Te/Metal Electrodes." Materials 16, no. 13 (June 24, 2023): 4569. http://dx.doi.org/10.3390/ma16134569.

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Photodetectors (PDs) based on two-dimensional (2D) materials have promising applications in modern electronics and optoelectronics. However, due to the intralayer recombination of the photogenerated carriers and the inevitable surface trapping stages of the constituent layers, the PDs based on 2D materials usually suffer from low responsivity and poor response speed. In this work, a distinguished GaN-based photodetector is constructed on a sapphire substrate with Te/metal electrodes. Due to the metal-like properties of tellurium, the band bending at the interface between Te and GaN generates an inherent electric field, which greatly reduces the carrier transport barrier and promotes the photoresponse of GaN. This Te-enhanced GaN-based PD show a promising responsivity of 4951 mA/W, detectivity of 1.79 × 1014 Jones, and an external quantum efficiency of 169%. In addition, owing to the collection efficiency of carriers by this Te–GaN interface, the response time is greatly decreased compared with pure GaN PDs. This high performance can be attributed to the fact that Te reduces the contact resistance of the metal electrode Au/Ti to GaN, forming an ohmic-like contact and promoting the photoresponse of GaN. This work greatly extends the application potential of GaN in the field of high-performance photodetectors and puts forward a new way of developing high performance photodetectors.

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Wang, Xingang, Tao Xiong, Kaiyao Xin, Juehan Yang, Yueyang Liu, Zeping Zhao, Jianguo Liu, and Zhongming Wei. "Polarization sensitive photodetector based on quasi-1D ZrSe₃." Journal of Semiconductors 43, no. 10 (October 1, 2022): 102001. http://dx.doi.org/10.1088/1674-4926/43/10/102001.

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Abstract The in-plane anisotropy of transition metal trichalcogenides (MX3) has a significant impact on the molding of materials and MX3 is a perfect choice for polarized photodetectors. In this study, the crystal structure, optical and optoelectronic anisotropy of one kind of quasi-one-dimensional (1D) semiconductors, ZrSe3, are systematically investigated through experiments and theoretical studies. The ZrSe3-based photodetector shows impressive wide spectral response from ultraviolet (UV) to near infrared (NIR) and exhibits great optoelectrical properties with photoresponsivity of 11.9 mA·W-1 and detectivity of ~106 at 532 nm. Moreover, the dichroic ratio of ZrSe3-based polarized photodetector is around 1.1 at 808 nm. This study suggests that ZrSe3 has potential in optoelectronic applications and polarization detectors.

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Yang, Feng, Kai Huang, Shibing Ni, Qi Wang, and Deyan He. "W18O49 Nanowires as Ultraviolet Photodetector." Nanoscale Research Letters 5, no. 2 (November 27, 2009): 416–19. http://dx.doi.org/10.1007/s11671-009-9499-z.

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39

Cao, Jin, Liang Chen, Xin Chen, Yu Zhu, Jianqi Dong, Baoyu Wang, Miao He, and Xingfu Wang. "Performance Improvement of Amorphous Ga2O3/P-Si Deep Ultraviolet Photodetector by Oxygen Plasma Treatment." Crystals 11, no. 10 (October 15, 2021): 1248. http://dx.doi.org/10.3390/cryst11101248.

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Gallium oxide (Ga2O3) is an attractive semiconductor that is very suitable for deep ultraviolet (DUV) inspection. However, due to the existence of many types of oxygen vacancies in the amorphous Ga2O3 (a-Ga2O3) film, it greatly limits the performance of the a-Ga2O3-based photodetector. Here, we perform oxygen plasma treatment on the a-Ga2O3/p-Si photodetector to reduce the concentration of oxygen vacancies in the a-Ga2O3 film, so that the dark current is reduced by an order of magnitude (from 1.01 × 10−3 A to 1.04 × 10−4 A), and the responsivity is increased from 3.7 mA/W to 9.97 mA/W. In addition, oxygen plasma processing makes the photodetector operate well at 0 V bias. The response speed is that the rise time is 2.45 ms and the decay time is 1.83 ms, while it does not respond to the DUV illumination without oxygen plasma treating at a zero bias. These results are attributed to the fact that oxygen plasma treatment can reduce the Schottky barrier between a-Ga2O3 and the electrode indium tin oxide (ITO), which promotes the separation and collection efficiency of photo-generated carriers. Therefore, this work proposes a low-cost method to improve the performance of Ga2O3 film-based DUV photodetectors.

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Mei, Tong, Shan Li, Shaohui Zhang, Yuanyuan Liu, and Peigang Li. "Simply equipped ε-Ga₂O₃ film/ZnO nanoparticle heterojunction for self-powered deep UV sensor." Physica Scripta 97, no. 1 (January 1, 2022): 015808. http://dx.doi.org/10.1088/1402-4896/ac476e.

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Abstract In this paper, a ε-Ga2O3 film/ZnO nanoparticle hybrid heterojunction deep ultraviolet (UV) photodetector is described for 254 nm wavelength sensing application. The constructed ε-Ga2O3/ZnO heterojunction photodetector can operate in dual modes which are power supply mode and self-powered mode. Under reverse 5 V bias with 254 nm light intensity of 500 μW cm−2, the photoresponsivity, specific detectivity and external quantum efficiency are 59.7 mA W−1, 7.83 × 1012 Jones and 29.2%. At zero bias, the advanced ε-Ga2O3/ZnO photodetector performs decent self-powered photoelectrical properties with photo-to-dark current ratio of 1.28 × 105, on/off switching ratio of 3.22 × 104, rise/decay times of 523.1/31.7 ms, responsivity of 4.12 mA W−1 and detectivity of 2.24 × 1012 Jones. The prominent photodetection performance lays a solid foundation for ε-Ga2O3/ZnO heterojunction in deep UV sensor application.

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Park, Sangbin, Younghwa Yoon, Hyungmin Kim, Taejun Park, Kyunghwan Kim, and Jeongsoo Hong. "A Self-Powered High-Responsivity, Fast-Response-Speed Solar-Blind Ultraviolet Photodetector Based on CuO/β-Ga2O3 Heterojunction with Built-In Potential Control." Nanomaterials 13, no. 5 (March 6, 2023): 954. http://dx.doi.org/10.3390/nano13050954.

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Controlling built-in potential can enhance the photoresponse performance of self-powered photodetectors. Among the methods for controlling the built-in potential of self-powered devices, postannealing is simpler, more efficient, and less expensive than ion doping and alternative material research. In this study, a CuO film was deposited on a β-Ga2O3 epitaxial layer via reactive sputtering with an FTS system, and a self-powered solar-blind photodetector was fabricated through a CuO/β-Ga2O3 heterojunction and postannealed at different temperatures. The postannealing process reduced the defects and dislocations at the interface between each layer and affected the electrical and structural properties of the CuO film. After postannealing at 300 °C, the carrier concentration of the CuO film increased from 4.24 × 1018 to 1.36 × 1020 cm−3, bringing the Fermi level toward the valence band of the CuO film and increasing the built-in potential of the CuO/β-Ga2O3 heterojunction. Thus, the photogenerated carriers were rapidly separated, increasing the sensitivity and response speed of the photodetector. The as-fabricated photodetector with 300 °C postannealing exhibited a photo-to-dark current ratio of 1.07 × 103; responsivity and detectivity of 30.3 mA/W and 1.10 × 1012 Jones, respectively; and fast rise and decay times of 12 ms and 14 ms, respectively. After three months of storage in an open-air space, the photocurrent density of the photodetector was maintained, indicating good stability with aging. These results suggest that the photocharacteristics of CuO/β-Ga2O3 heterojunction self-powered solar-blind photodetectors can be improved through built-in potential control using a postannealing process.

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Zeng, Chun Hong, Yong Jian Ma, Bao Shun Zhang, Ya Meng Xu, and Mei Kong. "Broadband Ultraviolet Photodetector Based on Graphene/β-Ga₂O₃/GaN Heterojunction." Materials Science Forum 1014 (November 2020): 131–36. http://dx.doi.org/10.4028/www.scientific.net/msf.1014.131.

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Broadband ultraviolet (BUV) photodetectors are widely used in military and civil fields. A high performance BUV photodetector based on graphene/β-Ga2O3/GaN heterojunction is proposed and realized by semiconductor micro-fabrication techniques in this paper. The β-Ga2O3 and GaN films are grown by metal organic chemical vapor deposition (MOCVD), and the graphene is also used as a transparent electrode. The device exhibits a broad response band from 230 nm to 368 nm with responsivity exceeding 0.4A/W at -5 V bias voltage and a peak responsivity of 0.53 A/W at 256 nm. These performances can be attributed to the internal gain mechanism of graphene/β-Ga2O3/GaN heterojunction and the optical properties of graphene. Our work provides an efficient method to realize a high-performance BUV photodetector for photoelectric applications.

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Cao, Rui, Ye Zhang, Huide Wang, Yonghong Zeng, Jinlai Zhao, Liyuan Zhang, Jianqing Li, et al. "Solar-blind deep-ultraviolet photodetectors based on solution-synthesized quasi-2D Te nanosheets." Nanophotonics 9, no. 8 (February 4, 2020): 2459–66. http://dx.doi.org/10.1515/nanoph-2019-0539.

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AbstractSolar-blind deep ultraviolet (DUV) photodetectors with high responsivity (R) and fast response speed are crucial for practical applications in astrophysical analysis, environmental pollution monitoring, and communication. Recently, 2D tellurium has emerged as a potential optoelectronic material because of its excellent photoelectric properties. In this study, solar-blind DUV photodetectors are demonstrated based on solution-synthesized and air-stable quasi-2D Te nanosheets (Te NSs). An R of 6.5 × 104 A/W at 261 nm and an external quantum efficiency (EQE) of higher than 2.26 × 106% were obtained, which are highest among most other 2D material-based solar-blind DUV photodetectors. Moreover, the photoelectric performance of the quasi-2D Te-based photodetector exhibited good stability even after ambient exposure for 90 days without any encapsulation. These results indicate that quasi-2D Te NSs provide a viable approach for developing solar-blind DUV photodetectors with ultrahigh R and EQE.

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Wang, Cheng-Jyun, Hsin-Chiang You, Jen-Hung Ou, Yun-Yi Chu, and Fu-Hsiang Ko. "Ultraviolet Photodetecting and Plasmon-to-Electric Conversion of Controlled Inkjet-Printing Thin-Film Transistors." Nanomaterials 10, no. 3 (March 4, 2020): 458. http://dx.doi.org/10.3390/nano10030458.

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Direct ink-jet printing of a zinc-oxide-based thin-film transistor (ZnO-based TFT) with a three-dimensional (3-D) channel structure was demonstrated for ultraviolet light (UV) and visible light photodetection. Here, we demonstrated the channel structures by which temperature-induced Marangoni flow can be used to narrow the channel width from 318.9 ± 44.1 μm to 180.1 ± 13.9 μm via a temperature gradient. Furthermore, a simple and efficient oxygen plasma treatment was used to enhance the electrical characteristics of switching ION/IOFF ratio of approximately 105. Therefore, the stable and excellent gate bias-controlled photo-transistors were fabricated and characterized in detail for ultraviolet (UV) and visible light sensing. The photodetector exhibited a superior photoresponse with a significant increase of more than 2 orders of magnitude larger drain current generated upon UV illumination. The results could be useful for the development of UV photodetectors by the direct-patterning ink-jet printing technique. Additionally, we also have successfully demonstrated that a metal-semiconductor junction structure that enables plasmon energy detection by using the plasmonic effects is an efficient conversion of plasmon energy to an electrical signal. The device showed a significant variations negative shift of threshold voltage under different light power density with exposure of visible light. With the ZnO-based TFTs, only ultraviolet light detection extends to the visible light wavelength.

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Гаврушко, В. В., А. С. Ионов, О. Р. Кадриев, and В. А. Ласткин. "Кремниевые дифференциальные фотоприемники. Технология, характеристики, применение." Журнал технической физики 93, no. 9 (2023): 1353. http://dx.doi.org/10.21883/jtf.2023.09.56223.136o-23.

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A silicon-based photodetector containing two identical n+-p photodiodes is described. One of the photodiodes had a wide spectral response with high sensitivity in the ultraviolet region. The sensitivity of the second was reduced in the short-wavelength part of the spectrum by creating additional recombination centers in the near-surface region by implanting As ions. The spectral sensitivity of the differential signal obtained by subtracting photocurrents had a pronounced short-wavelength characteristic. The long-wavelength limit of the spectral range in terms of the λ0.5 level, depending on the doping dose, was in the range of 0.37 — 0.47 μm. The sensitivity maximum corresponded to λmax=0.32 — 0.37 μm. The electrical and noise characteristics of the photodetector are given. The possibility of using differential photodetectors as two-color ones is shown.

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Pu, Yuhan, and Yung C. Liang. "High-gain high-sensitivity AlGaN/GaN ultraviolet photodetector with effective mechanism for photocurrent collection." Applied Physics Letters 121, no. 6 (August 8, 2022): 062105. http://dx.doi.org/10.1063/5.0095835.

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A high-performance AlGaN/GaN-based ultraviolet photodetector with a field-enhanced mechanism for photocurrent collection is designed and fabricated in this work. In addition to the inherent polarization field, two additional sets of collection fields are formed from a 2DEG layer to a ITO thin film and from the 2DEG layer to a cathode electrode sinker. The effectiveness in the collection of photogenerated carriers is remarkably enhanced, which leads to a photocurrent of 6.6 mA/mm under the illumination of 365 nm-centered ultraviolet light at an intensity of 1.8 mW/cm2. With an in-built shallow isolation trench, the dark current is suppressed below 40 pA/mm under a device bias of 5.0 V. A photo-to-dark current ratio as high as 1.7 × 108, a record high photo-responsivity over 4.3 × 106 A/W, and a high gain of 1.46 × 107 under 365-nm light are demonstrated by the fabricated prototype, showing great competitiveness in state-of-the-art AlGaN/GaN-based ultraviolet photodetectors.

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Rajan, Akshta, Kashima Arora, Harish Kumar Yadav, Vinay Gupta, and Monika Tomar. "Copper Doped ZnO Thin Film for Ultraviolet Photodetector with Enhanced Photosensitivity." MRS Proceedings 1494 (2013): 43–49. http://dx.doi.org/10.1557/opl.2012.1742.

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ABSTRACTUltraviolet photoconductivity in Copper doped ZnO (Cu:ZnO) thin films synthesized by sol-gel technique is investigated. Response characteristics of Pure ZnO thin film and Cu:ZnO thin film UV photodetector with 1.3 at. wt % Cu doping biased at 5 V for UV radiation of λ = 365 nm and intensity = 24 µwatt/cm2 has been studied. Cu:ZnO UV photodetector is found to exhibit a high photocoductive gain (K = 1.5×104) with fast recovery (T90% = 23s) in comparison to pure ZnO thin film based photodetector (K = 4.9×101 and T90% = 41s). Cu2+ ions have been substituted in ZnO lattice which has been confirmed by X-ray diffraction (XRD) and Raman spectroscopy leading to lowering of dark current (Ioff ∼ 1.44 nA). Upon UV illumination, more electron hole pairs are generated in the photodetector due to the high porosity and roughness of the surface of the film which favours adsorption of more oxygen on the surface of the photodetector. The photogenerated holes recombined with the trapped electrons, increasing the concentration of photogenerated electrons in the conduction band enhancing the photocurrent (Ion ∼ 0.02 mA) of the Cu:ZnO photodetector.

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Liu, Jinzhang, Nunzio Motta, and Soonil Lee. "Ultraviolet photodetection of flexible ZnO nanowire sheets in polydimethylsiloxane polymer." Beilstein Journal of Nanotechnology 3 (May 2, 2012): 353–59. http://dx.doi.org/10.3762/bjnano.3.41.

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ZnO nanowires are normally exposed to an oxygen atmosphere to achieve high performance in UV photodetection. In this work we present results on a UV photodetector fabricated using a flexible ZnO nanowire sheet embedded in polydimethylsiloxane (PDMS), a gas-permeable polymer, showing reproducible UV photoresponse and enhanced photoconduction. PDMS coating results in a reduced response speed compared to that of a ZnO nanowire film in air. The rising speed is slightly reduced, while the decay time is prolonged by about a factor of four. We conclude that oxygen molecules diffusing in PDMS are responsible for the UV photoresponse.

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Zhao, Zhihui, Di Wu, Jiawen Guo, Enping Wu, Cheng Jia, Zhifeng Shi, Yongtao Tian, Xinjian Li, and Yongzhi Tian. "Synthesis of large-area 2D WS2 films and fabrication of a heterostructure for self-powered ultraviolet photodetection and imaging applications." Journal of Materials Chemistry C 7, no. 39 (2019): 12121–26. http://dx.doi.org/10.1039/c9tc03866c.

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High-performance self-powered ultraviolet (UV) photodetector based on a WS₂/GaN heterojunction was demonstrated, which exhibits excellent UV photoresponse properties. Significantly, this photodetector has exhibited excellent UV imaging capability.

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HUANG, Zhijuan, Zhinong YU, Yan LI, and Jizheng WANG. "ZnO Ultraviolet Photodetector Modified with Graphdiyne." Acta Physico-Chimica Sinica 34, no. 9 (2018): 1088–94. http://dx.doi.org/10.3866/pku.whxb201801251.

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Journal articles on the topic 'Ultraviolet Photodetector'

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