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Spectral response of GaN-based p-i-n photodiodes (a) with a 0.2 µm thick GaN(p) layer, (b) with a 0.1 µm thick GaN(p) layer, (c) without a GaN(p) layer except the one located below the ohmic contact, and (d) spectral response of an Al 0.12 Ga 0.88 N(p)-GaN(i)GaN(n) photodiode (dashed line) (from 39 ).
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Ultraviolet detectors are of a great interest to a wide range of industrial, military, environmental and even biological applications. This paper intends first to review some of the most relevant recent developments in the field of wide bandgap semiconductor UV detectors, and to give an overview of their applications. A special focus is given on II...
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... a small diffusion length in the p-type layer induces a decrease of the responsivity at shorter wavelengths. This effect is enhanced by the use of thick surface layers, as shown on Figure 5. Nitride-based p-i-n detectors features display a sharp cutoff edge towards large wavelengths, whose energetic position is directly linked to the energy gap of the semiconductor material that is used for the active layer. ...
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Self-powered ultraviolet (UV) photodetectors, which have vast applications in the military and for civilian purposes, have become particularly attractive in recent years due to their advantages of high sensitivity, ultrasmall size, and low power consumption. In particular, self-powered UV photodetectors driven by a built-in electric field cannot on...
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... Solar-blind photodetectors (SBPDs) have attracted enormous attention because of their versatile applications in ultraviolet (UV) astronomy, missile warning, short-range communication security, flame detection, chemical/biological analysis, environmental detection, astronomical imaging, etc. [1][2][3][4][5][6][7]. Nowadays, several kinds of wide-band gap semiconductors including Al x Ga 1−x N, GaN, MgZnO, ZnO and SiC have been explored to fabricate SBPDs [8][9][10][11][12][13]. however, mismatched band gaps and inferior crystalline quality have halted their progression into the field of SBPDs [14][15][16]. ...
The wide band gap semiconductor Ga2O3 has become an excellent UV detection material due to its suitable band gap, high crystalline quality and thermal stability. In this paper, the microstructure of Ga2O3 with different thicknesses is characterized and the solar-blind detection performance of Ga2O3/p-Si heterojunctions are further investigated. XRD and UV–VIS demonstrate that Ga2O3 sputtered for 20 min is amorphous with a band gap of 4.98 eV, as the sputtering time increases, Ga2O3 grows along the (002) crystal plane and the band gap increases. XPS reveals that the lattice oxygen content in the Ga2O3 increases with the sputtering time, however, the Ga³⁺ content reaches a peak in Ga2O3 sputtered for 1.5 h. And the increasing of the binding energy between Ga-O in Ga2O3/p-Si heterojunctions accelerates response speed. Electrical experiments show that the heterojunction consisting of sputtered 1.5 h Ga2O3 and p-Si reaches a higher PDCR, with a value of 6684 at 5.7 V. Meanwhile, the rise and decay time of the heterojunction are 0.13 s and 0.14 s at 0 V, and the decay time gradually increases from 0.1 to 0.7 s with increasing the applied voltage. However, insertion of 20 nm Si-doped Ga2O3 as a hole-blocking layer at the interface of p-Si and Ga2O3 remarkably declines the decay time under various applied biases and causes no obvious damage to the photo current of the heterojunction.
... The UV detector is a device that converts light signals into electrical signals and is designed to detect UV light [3]. In recent years, UV detectors have been widely used in fields such as light curing, environmental monitoring, biomedicine, military, fire fighting, cultural relics protection, etc. [4][5][6][7][8][9]. Compared with traditional photoconductive UV detectors, a new type of photoelectrochemical (PEC) UV detector that has recently emerged has attracted much attention due to its advantages such as a simple preparation process, easy availability of raw materials, and no need for additional external voltage [10]. ...
Conventional sandwich structure photoelectrochemical UV detectors cannot detect UV light below 300 nm due to UV filtering problems. In this work, we propose to place the electron collector inside the active material, thus avoiding the effect of electrodes on light absorption. We obtained a TiO2-nanotubes@Ti@quartz photoanode structure by precise treatment of a commercial Ti mesh by anodic oxidation. The structure can absorb any light in the near-UV band and has superior stability to other metal electrodes. The final encapsulated photoelectrochemical UV detectors exhibit good switching characteristics with a response time below 100 ms. The mechanism of the oxidation conditions on the photovoltaic performance of the device was investigated by the electrochemical impedance method, and we obtained the optimal synthesis conditions. Response tests under continuous spectroscopy confirm that the response range of the device is extended from 300–400 nm to 240–400 nm. This idea of a built-in collector is an effective way to extend the response range of a photoelectrochemical detector.
... This specic range of light is commonly referred to as 'solar-blind' or the 'solar-blind band' due to its restricted reach. 1,2 The intensity of radiation in this solar blind region is signicantly lower than that in the visible region. Combined with the low natural background, photodetectors designed to operate within this spectral band offer several advantages, including a high signal-to-noise ratio, excellent sensitivity, and a relatively low false alarm rate. ...
Due to their high wavelength selectivity and strong anti-interference capability, solar-blind UV photodetectors hold broad and important application prospects in fields like flame detection, missile warnings, and secure communication. Research on solar-blind UV detectors for amorphous Ga2O3 is still in its early stages. The presence of intrinsic defects related to oxygen vacancies significantly affects the photodetection performance of amorphous Ga2O3 materials. This paper focuses on growing high quality amorphous Ga2O3 films on silicon substrates through atomic layer deposition. The study investigates the impact of annealing atmospheres on Ga2O3 films and designs a blind UV detector for Ga2O3. Characterization techniques including atomic force microscopy (AFM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) are used for Ga2O3 film analysis. Ga2O3 films exhibit a clear transition from amorphous to polycrystalline after annealing, accompanied by a decrease in oxygen vacancy concentration from 21.26% to 6.54%. As a result, the response time of the annealed detector reduces from 9.32 s to 0.47 s at an external bias of 10 V. This work demonstrates that an appropriate annealing process can yield high-quality Ga2O3 films, and holds potential for advancing high-performance solar blind photodetector (SBPD) development.
... Developing diamond-based UV photodetectors enabled detection in the range between UV and visible, with a short cut-off wavelength of λ c = 225 nm and high contrast (6 orders of magnitude) [122]. Diamond is characterized by numerous extraordinary properties among all semiconductors, such as the highest mechanical hardness. ...
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.
... It was generated only from artificial device sources such as sterilizers and arc xenon lamps for disinfecting air and water. Therefore, most PD research has been focused on UVA and UVB PD [13][14][15]. However, due to the destruction of the ozone layer by environmental pollution, UVC began to reach the earth's surface [16]. ...
Constitutive engineering by adding halide anions is one effective way to improve the performance of photodetectors by adjusting the bandgap. In this study, a mixed-anion perovskite thin film was facile fabricated by post-processing of a pure FAPbI3 film with a formamidinium bromide (FABr) solution. In addition, the manufactured thin film was used as the light absorption layer, SnO2-SDBS as the electron transport layer, and spiro-OMeTAD as the hole injection layer to fabricate a deep ultraviolet(UV) photodetector. The device exhibited a response of 43.8 mA/W−1, a detectability of 3.56 × 1013 Jones, and an external quantum efficiency of 38%. Therefore, this study is promising for various applications in the deep-UV wavelength region.
... Photocurrent is defined as the fraction of photogenerated electronhole (e --h + ) pairs collected at the semiconductor edges by the electrodes. In case of photodetectors, photocurrent can be estimated by the following formula [29,30]: (1) where, I Ph denotes photocurrent; I light and I dark are current achieved from device under light and dark conditions, respectively. ...
... It is typically following the absorption spectrum of the light-sensitive semiconducting material employed in the photodetector device. The photoresponsivity of the photodetector is given by the following expression [29,30]: ...
... The EQE is defined as the ratio of the number of e --h + pairs contributing to photocurrent creation to the total number of e --h + pairs formed by absorbing incoming light. The EQE (λ) formula calculates the ratio of charge carriers collected to absorbed photons [29,30]. ...
Nanostructured metal sulfides are the potential materials for the development of highly efficient photodetectors, attributed to their easily tunable physical, chemical, optical, and electronic properties. Especially, nanostructured arrays based on binary metal sulfides like ZnS, MoS2, CdS, SnS, WS2, PbS, and TiS3 with a strong light-matter interaction have sparked the interest of researchers as photosensor materials. This review provides the complete insight on the research progress of photodetectors based on nanostructured metal sulfide films, which are classified into three categories such as ultraviolet (UV), visible, and infrared (IR) photodetectors. Initially, the fundamentals of photodetectors with various figures of merit are discussed. For UV photodetection, the wide bandgap metal sulfides such as ZnS and SnS2 based devices are mostly reported. In case of visible photodetectors, CdS, WS2, and MoS2 based materials and their heterostructures are widely experimented towards the efficient photodetection. Finally, narrow bandgap and high surface-area to volume ratio quantum dot metal sulfides such as PbS, TiS3, and SnS based devices are reviewed for IR photodetection. Herein, to benchmark the device performance, the comparison of the standard figures of merit such as responsivity, detectivity, external quantum efficiency, and response time for various reported literature are carried out. Among all metal sulfide-based photodetectors, ZnS/graphene heterostructure, ReS2-based photodetector, and PbS/graphene-based phototransistor have higher device characteristics under UV, visible, and IR illumination, respectively. To conclude, the review has been completed with the summary of the recent progress and future aspects for next generation photodetector devices.
... Phototransistors based on wide-bandgap semiconductors have exhibited favorable potential for applications such as military early warning, optical communication, remote sensing, and biochemical detection [1][2][3][4][5]. To date, conventional wide-bandgap semiconductors, specifically Ga 2 O 3 [6][7][8][9], have always been considered as prospective candidates for practical commercial manufactures. ...
Transition metal phosphorous trichalcogenides (MPX3) have been extensively investigated as photodetectors due to their wide-bandgap semiconductor properties. However, the research involved in the photoresponses at low temperatures remain blank. Here, hexagonal boron nitride (hBN)-encapsulated NiPS3 field effect transistors were fabricated by using the dry-transfer technique, indicating strong stability under atmospheric environments. The NiPS3 devices with the thickness of 10.4 nm, showed broad photoresponses from near-infrared to ultraviolet radiation at the liquid nitrogen temperature, and the minimum of rise time can reach 30 ms under the wavelength of 405 nm. The mechanism of temperature-dependent photoresponses can be deduced by competition between Schottky barrier height and thermal fluctuation. Our findings provide insights into superior phototransistors in few-layered NiPS3 for ultrasensitive light detection.
... (1) and (2) Figure 5 shows the responsivity (R e ) of the of proposed device with wavelength ranging from 0.0 µm to 1.2 µm by taking same parametric values which are used to calculate the I ap; with different values of work-function for metal 1(Φ M1 ) and metal 2 (Φ M2 ) such as 4.83 eV and 4.41 eV respectively. The peak value of R e has been observed at wavelength (λ) = 0.450 µm and it lies in the visible region of spectrum as shown in Fig. 5. Hence, proposed DMG CL-NWMOSFET works powerfully as a visible photodetector, which is highly recommended for various biological and sensing applications [36,37]. Figure 6 show the curve between percentage Quantum Efficiency (Q e ) and different wavelength (λ) of the channel. ...
This paper proposed a highly sensitive Double Metal Gate-stacking Cylindrical Nanowire-MOSFET (DMG CL-NWMOSFET) photosensor by using In1 − xGaxAs. For the best control of short channel effects (SCEs), a double metal gate has been utilized and for efficient photonic absorption, III-V compound has been utilized as channel material. The currently available Conventional Filed-Effect-Transistors (CFET) based photosensor have been used threshold voltage as parameter for the calculation of sensitivity, but in the proposed photosensor, change in subthreshold current has been used as the detecting parameters for sensitivity (Iillumination/Idark). The scientifically electrons study and the photo-conductive characteristics of In1 − xGaxAs CL-NWMOSFET are taken through Silvaco Atlas Tools with two work-functions 4.83 eV and 4.41 eV of metal 1 and metal 2 respectively. After the analysis of In1 − xGaxAs dual Metal Gate Stacking Cylindrical NWMOSFET responds to detectable spectrum (~ 450 nm), incidents light with constant, reversible and fast response by responsivity (4.3 mAW− 1), high Iillumination/Idark (1.36 * 109) and quantum-efficiency (1.12 %). The obtained results of In1 − xGaxAs DMG CL-NWMOSFET based photodetectors have the potential in optoelectronics applications.
... A. General discussion: Material quality, substrate, doping, and dark current There are several excellent review articles [20][21][22] and book chapters 23 published on the status of AlGaN deep-UV detectors, including those that include reviews of Ga 2 O 3 -based counterparts as well. 24 Many of these reviews have provided extensive and exhaustive coverage of all aspects of AlGaN UV detectors including the status on material growth 25 and doping, structural qualities, device development efforts, and the exploration of UV FPAs based on the same. ...
This Perspective seeks to understand and assess why ultrawide bandgap (UWBG) semiconductor-based deep-UV photodetectors have not yet found any noticeable presence in real-world applications despite riding on more than two decades of extensive materials and devices’ research. Keeping the discussion confined to photodetectors based on epitaxial AlGaN and Ga 2 O 3 , a broad assessment of the device performance in terms of its various parameters is done vis-à-vis the dependence on the material quality. We introduce a new comprehensive figure of merit (CFOM) to benchmark photodetectors by accounting for their three most critical performance parameters, i.e., gain, noise, and bandwidth. We infer from CFOM that purely from the point of view of device performance, AlGaN detectors do not have any serious shortcoming that is holding them back from entering the market. We try to identify the gaps that exist in the research landscape of AlGaN and Ga 2 O 3 solar-blind photodetectors and also argue that merely improving the material/structural quality and device performance would not help in making this technology transition from the academic realm. Instead of providing a review, this Perspective asks the hard question on whether UWBG solar-blind detectors will ever find real-world applications in a noticeable way and whether these devices will be ever used in space-borne platforms for deep-space imaging, for instance.
... To further illustrate interpretation of global and local modeling approaches, we present another case study, using modeling of wide bandgap vs non-wide bandgap vdW semiconductor materials. Materials that exhibit large bandgaps are essential for high-temperate and high-power device applications due to their ability to maintain electronic functionalities at high ambient temperature environments [55][56][57][58]. Furthermore, multiple studies of vdW materials in the past decade have led to a recent surge of interest in wide bandgap vdW materials for next-generation electronic devices [59][60][61][62][63][64]. ...
Traditionally, materials discovery has been guided by basic physical rules, and such rules embody the basic understanding of the physical characteristics of interest of the material. However, the discovery of physical rules remains a challenging task due to the inherent difficulty in recognizing patterns in the high-dimensional and highly nonuniform distributed materials space. The standard data analytics approach using machine learning (ML) may fall short in producing meaningful results due to fundamental differences between the underlying assumptions and goals of ML vs materials discovery. ML is mainly focused on estimating complex black-box predictive models (that are nonlinear and multivariate), whereas in materials discovery, the goal is to come up with interpretable data-driven physical rules. Here, we attempt to tackle this problem by proposing a robust data analytics framework that allows us to derive basic physical rules from data. We introduce the concept of global and local modeling, utilizing both supervised and unsupervised learning, for highly nonuniformly distributed materials data. To enhance the model interpretation, we also introduce a model-independent interpretation technique to assist human experts in extracting useful physical rules. The proposed framework for extracting data-derived physical rules at the global and local level is illustrated using two case studies: (1) classification of van der Waals (vdW) and non-vdW (nvdW) materials and (2) classification of wide bandgap and non-wide bandgap vdW materials.
