Photodetectors Research Articles

Self-powered photodetector based on a CsPbBr3/n-Si Schottky junction

Self-powered photodetectors (SPPDs) are attracting considerable publicity due to their superiority over conventional photodetectors (PDs) in terms of high sensitivity, fast response, and no need for an external power supply. Halide perovskites are much anticipated in SPPDs for their unusual photoelectronic properties. This work developed a Schottky junction CsPbBr3/n-Si SPPD by growing stable all-inorganic CsPbBr3 microcrystals on an n-Si substrate using a solution method. At zero bias, such Schottky SPPD has a very weak dark current (0.3 pA), a wide linear dynamic range (LDR, 110 dB), a sizeable on–off ratio (>103), and high detectivity (1.05×1011Jones). Through the research of this project, it is expected to obtain a way to prepare Schottky photodiodes with high stability and self-driving capability.

Self-powered AlGaN-based MSM solar-blind ultraviolet photodetectors with high Al-content AlxGa1−xN/AlyGa1−yN asymmetrical heterostructure

An Al0.4Ga0.6N-based metal–semiconductor–metal (MSM) ultraviolet (UV) photodetector (PD) based on intentionally asymmetrical polarized Al0.55Ga0.45N/Al0.4Ga0.6N/Al0.65Ga0.35N heterostructure has been fabricated and investigated, which achieves the self-powered capabilities. Operated at zero bias, the device presents an ultralow dark current of 7.8 × 10−13 A, a high peak responsivity of 0.04 A/W at ∼275 nm, a cut-off wavelength at ∼285 nm, and a corresponding detectivity of 3.1 × 1012 Jones. In comparison, the device with symmetrical heterostructure has no response at 0 V, confirming the effect of the proposed asymmetrical MSM structure. Furthermore, it is expressly demonstrated that the structure provides an asymmetrical energy band due to different barrier heights at the metal/Al0.4Ga0.6N and metal/Al0.55Ga0.45N/Al0.4Ga0.6N Schottky contacts and enhances the built-in electric field in the Al0.4Ga0.6N active layer owing to its polarization effect through simulations theoretically. Therefore, the improvement of photogenerated carrier transport can be obtained at 0 V, contributing to the high-performance self-powered UV PD.

Enhancing the performance of Self-Powered Deep-Ultraviolet photoelectrochemical photodetectors by constructing α-Ga2O3@a-Al2O3 Core-Shell nanorod arrays for Solar-Blind imaging

With the advancement of Ga2O3-based deep-ultraviolet (DUV) photodetectors (PDs), the integration of PDs into array image sensors has become a sought-after objective. However, while solar-blind imaging research primarily revolves around solid-state Ga2O3-based PDs, there remains a significant gap in the exploration of novel photoelectrochemical (PEC) PDs for solar-blind imaging applications. In this study, self-powered solar-blind PEC-PDs with enhanced performance are fabricated based on α-Ga2O3@a-Al2O3 core–shell nanorod arrays (NRAs). Under DUV irradiation and without external bias, the α-Ga2O3@a-Al2O3 devices demonstrate remarkable superiority over α-Ga2O3 devices. When the light intensity was at 0.50 mW cm−2, the photocurrent density notably rises from 4.60 to 11.24 μA cm−2, accompanied by a corresponding increase in responsivity from 9.60 to 22.70 mA W−1. The enhanced performance is attributed to the α-Ga2O3@a-Al2O3 heterostructure, which establishes a built-in electric field facilitating the separation and directed transport of photogenerated carriers at the interface. Moreover, for the first time, a 5 × 5 matrix of α-Ga2O3@a-Al2O3 core–shell NRAs-based PEC-type PDs is employed to demonstrate a proof-of-concept for self-powered solar-blind imaging, capable of effectively capturing the shapes of the letters “C” and “N”. This work underscores the immense potential of Ga2O3-based PEC-type PDs for future large-area solar-blind imaging applications.

Design and optimization of the performance of self-powered Sb2S3 photodetector by SCAPS-1D simulation and potential application in imaging

Antimony sulfide (Sb2S3) is considered an excellent semiconductor material for visible light photodetectors (PDs) due to the non-toxicity, stability and high visible photon absorption coefficient. However, the deep physical cascade relationship between Sb2S3 devices and key parameters, such as the thickness, the doping density, the defect density, and the inverse contact of the figure of merit, has not been thoroughly investigated. In order to systematically explore the impact of parameters on Sb2S3 device performance, self-powered optoelectronic devices of TiO2/Sb2S3 p-n heterojunction were simulated by using one-dimensional (SCAPS-1D) software. Base on simulation, we learned that the optimum thickness of Sb2S3 is about 400 nm, the donor and acceptor densities of TiO2 and Sb2S3 layers are 1020 and 1016 cm−3, respectively. In addition, Au was chosen as the back electrode, and the high-quality Sb2S3 functional layer required a defect density of less than 1016 cm−3. Based on the guidance of simulation results, we finally fabricated the FTO/TiO2/Sb2S3/Au self-powered photodetectors. Under an illumination intensity of 3 μW/cm2 at 530 nm, the responsivity (R) and specific detectivity (D*) of the device can be up to 0.357 A/W and 5.1 × 1011 Jones, respectively. Particularly, the device exhibits a fast response with a response time of 1.4 μs and 3 dB bandwidth of 383 kHz. In this regard, we constructed a single-pixel scanning imaging system around the Sb2S3 detector and showed excellent imaging results, which provided a new path for us to develop a new type of visible light detector and imaging system.

Ultraviolet photo-memory with image storage functions by controlling carriers’ lifetime

Ultraviolet (UV) photodetectors (PDs) have been widely developed for multifunctional applications such as flame detection, space communication and missile detection etc. However, limited attention has been paid to developing UV PDs with photo-memory capabilities, despite their enormous potential for applications in the field of imitating human learning and memory. In this work, we propose a ZnS/ZnO/ZnS heterojunction for UV optoelectronic synapse with optoelectronic memory functions. Through the incorporation of a ZnS shell layer, we achieved a substantial enhancement in the near-band photoluminescence of ZnO and a marked improvement in the lifetime of photo-generated carriers. The ZnS/ZnO/ZnS-3 h UV PD demonstrate a responsivity of 3.6 A/W (5 V bias 0.28 mW/cm2 365 nm light.), which is 12 times of that of ZnO UV PD (0.3 A/W). Additionally, by controlling the thickness of ZnS shell, we extend the decay time of ZnS/ZnO/ZnS-3 h UV PD from 95 s (ZnO) to 378 s, indicating its potential for UV image storage. Also, it shows versatile synaptic functions, including photonic potentiation, paired-pulse facilitation, short-/long-term memory, as well as a “learning” behavior. These results show that UV PDs with long decay time have new potential applications in UV image storage.

Scalable Fabrication of High-Performance Self-Powered a-MoSe2 Thin-Film-Based Photodetectors on a-SiO2/Si Substrates.

Owing to its high stability, suitable absorption band gap, and fast response time, MoSe2 has attracted the most attention in transition-metal dichalcogenides (TMDCs) for photodetector (PD) applications. In this study, based on centimeter-scale smooth amorphous MoSe2 (a-MoSe2) thin films with thicknesses varying from 6.5 to 62.5 nm on a-SiO2/Si substrates prepared by polymer-assisted deposition, metal-semiconductor-metal-structured self-powered a-MoSe2 PDs are designed and fabricated. Our data show that the PD based on 9.5 nm thick a-MoSe2 thin film exhibits the highest values of photocurrent (Iph, 4.60 μA), photo-to-dark current ratio (PDCR, 3067), photoresponsivity (Rλ, 0.94 mA/W), and detectivity (D*, 4.29 × 1010 Jones), as well as the lowest values of noise-equivalent power (NEP, 2.33 × 10-11 W/Hz1/2) and photoresponse rise/decay time (61/58 ms) under a 405 nm laser with 5 mW power at zero bias, which are better than or comparable with those of previously reported PDs based on crystalline MoSe2 monolayers or other atomically thin 2D materials under bias voltage. The high-performance mechanism can be explained in terms of the energy band theory and volume modulation photoconductive gain model in a-MoSe2 with a spontaneous built-in electric field. Our work provides a scalable low-cost way for the design and fabrication of high-performance self-powered TMDC PDs.

Sensitivity analysis of TMD TFET based photo-sensor for visible light detection: A simulation study

This paper reports the sensitivity analysis of double gate TFET using the Transition Metal Di chalcogenide (TMD) material in photo sensitive region with the help of technology computer aided design (TCAD) simulator tool. The sensitivity analysis elaborates the significance of TMD material for optical applications. The photo sensitivity analysis is exhibited for the variation in wavelength (λ) of incident light under the visible range of spectrum. Furthermore, we have executed the performance of photo sensor by varying the position of illumination window. Result reveals that sensitivity, responsivity, and quantum efficiency of sensor are improved at λ = 320 nm. The maximum value of signal to noise ratio (SNR) and responsivity (R) are 63.2 dB and 106, respectively, under the visible range. This TMD material based TFET photo-sensor will be useful for the next generation low power highly sensitive optical devices.

Solar-blind ultraviolet-visible dual-spectral photodetector based on carbon nanodots/flexible-silicon heterojunction

Flexible solar-blind ultraviolet (UV) photodetectors (PDs) have important applications in biomedical and wearable electronic devices. Herein, a dual-spectral carbon nanodots/flexible n-silicon heterojunction photodetector is reported that always shows a photo response in UV illumination, while in visible illumination there is a photo response only in forward bias. The working mechanism of the carbon nanodots/silicon heterojunction was investigated. At 5 V bias, the responsivity of the device was 30.5 mA/W and 93.7 mA/W under the 254 nm illumination and the visible illumination, respectively. And the detectivity was 1.61 × 1011 Jones and 2.14 × 1011 Jones, respectively. The photocurrent of the device can reach 91 % or more of the original under the 0–0.6 % bending strain.

Non-orthogonal multiple access in a radio over fiber link based on optical-domain power allocation.

Non-orthogonal multiple access (NOMA) in a radio over fiber (RoF) link based on optical-domain power allocation is proposed and demonstrated. The NOMA is implemented at the RoF transmitter where two spectrum-overlapped microwave vector signals with an identical power level are modulated on an optical carrier to generate two orthogonally polarized optical signals. By passing the optical signals through a polarization controller (PC) and a polarizer, the power levels of the two optical signals are controlled to achieve optical power allocation (OPA). The optical signals are then transmitted over a fiber to the receiver. Since the power levels of the two microwave vector signals applied to the modulator are identical and the power allocation is implemented in the optical domain, the nonlinearity due to the higher-power input microwave vector signal is reduced, leading to an increase in the dynamic range. At the receiver, the two optical signals are detected at a photodetector (PD). To demultiplex the two microwave vector signals, a digital signal processing (DSP) algorithm is developed. The proposed approach is evaluated experimentally. The results show that the transmission performance in terms of error vector magnitude (EVM) is improved thanks to the increased dynamic range.

Enhanced self-driven ultraviolet photodetection performance of high-k Ta2O5/GaN heterostructure

Recently, high-k dielectric oxide-based MIS type ultraviolet (UV) photodetectors (PDs) have engrossed the researchers in the area of optoelectronics owing to their superior properties. The current work focuses on the preparation of symmetric interdigitated Au electrodes on Ta2O5/GaN heterojunction and to check its functioning as a photosensor in UV region. The impact of post-annealing procedure on the bandgap, crystalline quality, surface morphology and chemical composition has been investigated using UV-VIS, XRD, AFM and XPS techniques, respectively. The evaluated optical bandgaps from the Tauc's plots for the Ta2O5 films ranging from 4.52 eV to 4.92 eV. XRD analysis showed the formation of an orthorhombic phase after post-annealing temperature of 700 °C. The post-annealed Ta2O5 film surface morphology comprises prearranged atomic clusters with spherical shapes. The XPS exploration revealed the occurrence of the Ta5+ state and confirmed the formation of Ta2O5 phase. Photodetection parameters of the designed Au/Ta2O5/GaN MIS BB PDs are studied using I–V, responsivity and temporal responses as a function of the post-annealing process. At 0 V bias, with the illumination of 310 nm UV light, the 800 °C post-annealed MIS PD device exhibited peak responsivity of 212 mA/W, external quantum efficiency (EQE) of 86.8 % and detectivity of 1.5 × 1013 Jones. Further, under self-driven mode with 350 nm light illumination, the 800 °C post-annealed UV PD device generated faster rise and fall times of 90 ms and 790 ms, respectively. The post-annealed Au/Ta2O5/GaN heterostructure PD device demonstrates improved photoresponsivity, EQE and rise/fall times compared with the as-deposited PD device. This remarkable improvement in the photodetection performance is attributed to the best band configuration of the Ta2O5/GaN heterostructure because of substantial post-annealing process and facilitating broadband absorption from UV-C to A region with quicker generation, separation and transportation of photogenerated charge carriers. Consequently, the current research work emphasizes the significance of the combination of UV sensing Ta2O5 high-k oxide and n-GaN materials to serve the future necessities of the photodetection technology under self-driven mode i.e., without any external bias.

UV photodetector study based on Ce: ZnO nanostructures with different concentration of Ce dopant

UV photodetectors (PDs) find pivotal roles across diverse domains like space exploration, radiation monitoring, and electronics. Zinc oxide (ZnO), an n-type semiconductor with a wide bandgap, stands out as an attractive material for photodetection due to its remarkable UV responsivity. This study centers on assessing the role of Ce doping in enhancing the UV sensitivity of ZnO-based photodetectors when subjected to laser illumination (excitation wavelength: 374 nm). Synthesized through a hydrothermal approach, Zn1-xCexO nanostructures with varying concentrations (x = 1.5, 3.5, 5.5, and 7.5 wt%) were subsequently deposited onto ZnO nanorods (NRs) via tape casting. A comprehensive array of characterization techniques was employed to analyze the structural, morphological, and optoelectrical properties of Ce:ZnO. Incorporating Ce to ZnO lattice induced a reduction in the density of oxygen vacancies, culminating in an enhancement of optoelectronic performance. This improvement encompassed aspects such as photocurrent and responsivity within a p-n heterojunction Ce: ZnO–Cu2O (CZC) UV-PD setup. The introduction of cerium led to a slight shift in the band gap energies, from 3.18 eV for pristine ZnO to 3.23–3.19 eV for the CZ samples. Impressively, Ce-doped ZnO (5.5 wt%) nanostructures exhibited enhanced performance in UV detection, showcasing a detectivity of approximately ∼42 × 109 (Jones), an expedient rise time of under 0.1 s, and a desirable decay time of 8.7 s for the CZC-3%.

Mg content regulating built-in electric field for self-powered ZnO/MgxZn1-xO Schottky UV photodetector

In recent years, self-powered Schottky ultraviolet (UV) photodetectors (PDs) have attracted great attention due to their low manufacturing cost and zero-bias response. However, the development of high-performance self-powered Schottky devices is limited by the weak light response due to the internal weak electric field. Here, we introduce a MgxZn1-xO capping layer on ZnO and fabricate a ZnO/MgxZn1-xO heterojunction Schottky UV PD by using the sol-gel method. The improved device exhibits excellent self-powered characteristics and stability, specifically, an increase of 909% in photocurrent, an improvement of more than one order of magnitude in responsivity, and an improved linear dynamic region (LDR: 33.7 dB). The introduction of the MgxZn1-xO capping layer is responsible for the improved device performance, resulting in enhanced built-in electric field and depletion region width due to the increase of the Schottky barrier, thereby facilitating the separation and transport of photogenerated carriers. This work provides an effective way to fabricate high-performance self-powered ZnO Schottky UV PDs.

Enhanced photoresponse of self-powered ZnO-based photoelectrochemical-type UV photodetectors via Ga-doping for optical communication application

Wide-bandgap metal-oxide semiconductors hold promise for self-powered photoelectrochemical (PEC) type UV photodetectors (PDs) due to their inherent photoelectric properties and durability. However, inadequate charge carrier separation and transport remain a fundamental challenge for practical applications. Herein, the extraordinary efficacy of introducing gallium (Ga) into ZnO nanowire to design high-performance PEC-type PDs is demonstrated. The obtained Ga-doped ZnO (ZnO:Ga) PEC-type photodetectors exhibit superior UV photoresponse performance, featuring an exceptionally high responsivity of 233.26mA/W, an excellent detectivity of 4.18 × 1012 Jones, and a fast response/recovery time of 159/150 ms under 365nm illumination without external bias voltages. These accomplishments outperform the majority of previously reported PEC-type UV PDs. It is found that the unique properties of ZnO:Ga nanowires, including improved donor density and steeper band bending at solid-liquid interface, significantly enhance the generation, transfer, and separation of photoexcited charge carriers, thus contributing to the superior photodetector’s performance. In addition, a secure UV communication system using international Morse code is set to demonstrate the feasibility of ZnO:Ga nanowires PEC-PD as a self-powered optical receiver. This study introduces a promising approach to develop self-powered photodetectors that are highly stable, cost-effective, and poised for integration into future multifunctional optoelectronic devices.

MSM UV photodetector with low dark current based on GaInO/SrTiO3 heterojunction

Doping and heterojunction manufacturing processes are widely employed techniques for modifying the energy band of wide band gap semiconductors. In this work, the sol-gel method was employed to introduce indium (In) into Ga2O3, leading to the formation of the GaInO (GIO) thin film, which was subsequently combined with SrTiO3 (STO) to form the heterojunction. The heterojunction was utilized for the fabrication of metal-semiconductor-metal (MSM) structured ultraviolet (UV) photodetectors (PDs). The existence of a built-in electric field (Ebi) generated by the heterojunction at the contact interface of GIO and STO can diminish the density of majority carriers in dark conditions, consequently leading to a decrease in the dark current. The photo-to-dark suppression ratio of GIO/STO exceeds three orders of magnitude (1.157 × 103), and the dark current of the composite GIO/STO MSM UVPDs (0.178 nA) is one order of magnitude lower than that of the individual GIO (4.028 nA) at 5V bias. Additionally, the Ebi may accelerate the exciton separation for photo-generated exciton, thereby accelerating the response speed. The GIO/STO device demonstrates a shorter rise time of 1.21 s and a decay time of 0.42 s. The utilization of both energy band modification methods offers promising prospects for the application of GIO/STO MSM UVPDs.

Chiral-Achiral Cations Intercalation Induced Lead-Free Chiral-Polar Hybrid Perovskites Enable Self-Powered X-Ray and Ultraviolet-Visible-Near-Infrared Photo Detection.

Lead halide hybrid perovskites have made great progress in direct X-ray detection and broadband photodetection, but the existence of toxic Pb and the demand for external operating voltage have severely limited their further applications and operational stability improvements. Therefore, exploring "green" lead-free hybrid perovskite that can both achieve X-ray detection and broadband photodetection without external voltage is of great importance, but remains severely challenging. Herein, using centrosymmetric (BZA)3BiI6 (1, BZA = benzylamine) as a template, a pair of chiral-polar lead-free perovskites, (BZA)2(R/S-PPA)BiI6 (2-R/S, R/S-PPA = (R/S)-1-Phenylpropylamine) are successfully obtained by introducing chiral aryl cations of (R/S)-1-Phenylpropylamine. Compared to 1, chiral-polar 2-R presents a significant irradiation-responsive bulk photovoltaic effect (BPVE) with an open circuit photovoltage of 0.4V, which enables it with self-powered X-ray, UV-vis-NIR broadband photodetection. Specifically, 2-R device exhibits an ultralow detection limit of 18.5nGys-1 and excellent operational stability. Furthermore, 2-R as the first lead-free perovskite achieves significant broad-spectrum (377-940nm) photodetection via light-induced pyroelectric effect. This work sheds light on the rational crystal reconstruction engineering and design of "green" hybrid perovskite toward high-demanded self-powered radiation detection and broadband photodetection.

Enhanced photoresponsivity in Bi2Se3 decorated GaN nanowall network-based photodetectors

Recently, highly responsive photodetectors which are capable of photodetection in a wide range of wavelength spectra are in great demand. To fulfil this, photodetectors formed using heterojunctions of multiple semiconducting materials gain a lot of interest as they cover a broad range of photodetection, and the built-in electric field developed at their interface helps to enhance photoresponse. Here, we have demonstrated a fascinating broadband metal-semiconductor-metal type photodetector (PD) by integrating sputtered Bi2Se3 with the laser molecular beam epitaxy (LMBE) grown GaN film and porous nanowall network on sapphire (0001) substrates. The fabricated photodetectors using a hybrid Bi2Se3/LMBE-GaN nanowall structure exhibit broadband characteristics with a high responsivity of 51.4 and 1.46 A/W when illuminating with the laser of wavelength 355 nm (UV) and 1064 nm (NIR), respectively. The enhanced UV responsivity and good response in the NIR region using Bi2Se3/GaN heterojunction nanostructures suggest futuristic application in dual-wavelength detector devices.

Photonic generation of a tunable multi-band linearly frequency-modulated waveform

A photonic-assisted tunable multi-band linearly frequency-modulated (LFM) waveform generator based on optical heterodyne detection is proposed and experimentally demonstrated. The multi-band LFM waveform is generated from a photodetector (PD), where a broadband LFM optical pulse and a multi-wavelength optical signal with the same magnitude at different wavelengths are heterodyne-detected. The LFM optical pulse is generated from a three-electrode distributed Bragg reflector laser diode (DBR-LD). The multi-wavelength optical signal is produced through a Mach-Zehnder modulator (MZM), in which a light wave from an optical fiber laser (OFL) is nonlinearly intensity-modulated by a radio frequency (RF) signal. By tuning the wavelength of the LFM optical pulse lower than that of the multi-wavelength optical signal, a multi-band LFM waveform is generated at the PD. The center frequency of the generated LFM waveform can be adjusted by manipulating the wavelength of the OFL. The versatility in the bandwidth and temporal duration of the LFM waveform is attained through the precise tuning of the LFM optical pulse. The tuning of the center frequency difference between frequency bands is performed by altering the frequency of the RF signal. Experimental results have corroborated the realization of a tunable multi-band LFM waveform generator. The bandwidth and temporal duration of each band and the center frequency difference between frequency bands have tuning ranges from 0.7 to 6.7 GHz, 1 to 50 μs, and 2 to 6.7 GHz, respectively. The demonstration shows new avenues to implement high-performance multi-band LFM waveform generators for applications in multi-functional modern radar systems.

Study on the structural, optical and electrical properties of N-doped Ga2O3 films synthesized by sol-gel method

Ga2O3 exhibits great potential for applications in solar-blind ultraviolet photo detector, high-power electronic devices and solid-state light-emitting due to its ultra-wide band gap and high Baliga figure of merit. Here, Ga2(NxO1-x)3 films with varied nitrogen contents were prepared by the sol-gel technique. XRD analysis reveals that nitrogen doping contributes for growth of greater crystalline and SEM-EDS measurements confirm that the monoclinic crystal structure of Ga2(NxO1-x)3 is maintained to doping level of 3.26wt%; FTIR information indicates that nitrogen prefers to substitute for the O1 and O2 site of Ga2O3; XPS offers evidence that nitrogen tends to occupy oxygen vacancies and generate more gallium vacancies; UV-VIS shows that impurity defects appear above valence band, and the absorption position undergoes a red shift with nitrogen above 1.32wt%; PL shows Ga2(NxO1-x)3 films can emit light of various colors under excitation at 325nm, and the acceptor level is at 1.63eV∼2eV above the valence band; The conductivity of Ga2(NxO1-x)3 films is changed from n-type to p-type when nitrogen-doping is 0.96 wt% and the I–V curve composed of Ga2(NxO1-x)3 and Ga2O3 shows PDCR = 43 under the 254nm light. Therefore, the development of nitrogen-doped β-Ga2O3 has potential opportunities for applications in photoelectric devices.

Performance analysis of P-SnS thin films fabricated using CBD technique for photo detector applications

In the present work, SnS thin films were prepared using the CBD technique at room temperature and varying annealing temperaturesfrom300 to 450 °C for photo detector applications. The prepared samples were characterized using different techniques for analyzing the structural, optical, morphological, and photo sensing properties of the samples. From XRD analysis, the diffraction pattern of all the prepared thin films shows the pristine SnS phase of the samples possessing an orthorhombic phase without the presence of any impurity phases. Among the fabricated thin films, the SnS thin film annealed at a temperature of 350 °C reveals the highest crystallite size. The Raman results showed the vibrational modes of SnS films and with the increase in growth temperature, the peaks are slightly shifted towards the lower wavelength region. Morphological results show that the SnS thin films exhibit a uniform morphology of 2-D petal-like morphology with different sizes. The UV-vis spectroscopic study shows the decrease in the bandgap value of the samples with the increase in annealing temperature. The photo sensing properties of the fabricated samples show the SnS sample annealed at 400 °C has a higherresponsivityvalueof6.40×10⁻²AW⁻¹,externalquantumefficiency(EQE)valueof14.9%, and the detectivity value of 6.05 × 10⁹ Jones. Finally, the transient photo response results suggest that the SnS annealed at 350 °C shows a rise and fall time of 1.5 and 2.5 s compared to the othersampleswhichwouldbebettersuitedforphotodetectorapplications. The electrical conductivity and photo-conductivity of the films increase by more than two orders with increase of film thickness from 170 nm to 915 nm. Hall Effect measurements confirm the p-type nature of the as-prepared SnS thin films.

Sensing performance of β-Ga2O3 metal–semiconductor-metal deep ultraviolet photodetectors with refractory TiW electrodes at high temperatures

Given the critical impact of high-temperature environments on the detection performance and stability of deep ultraviolet (DUV) photonic devices, especially in urgent demands from fields including high-temperature industries and flame detection, the research on high-temperature resistant DUV photodetectors (PDs) has become of utmost importance. Due to its intrinsic high-temperature resistance, β-Ga2O3 holds significant potential in the field of DUV photodetection under elevated temperature environments. The conventional electrode material, titanium, typically exhibits poor high-temperature performance, while interfaces are susceptible to degradation at elevated temperatures. In this study, we fabricated β-Ga2O3 metal–semiconductor-metal (MSM) PDs using the refractory metal TiW as the electrode, and investigated their DUV detection performance across the temperature range of 300 to 800 K. Favorable performance was achieved at room temperature, with a photo-to-dark current ratio (PDCR) of 3.1 × 106, a responsivity (R) of 0.2 A/W, a detectivity (D*) of 8.3 × 1013 Jones, and an external quantum efficiency (EQE) of 102.3 %. However, an increase in operating temperature led to a continuous rise in dark current (Idark) and a decrease followed by an increase in photocurrent (Iphoto). In an 800 K operating environment, the PDCR decreased to 4.4 × 102, R increased to 0.7 A/W, D* dropped to 2.0 × 1012 Jones, and EQE improved to 343.7 %. Furthermore, the temperature-dependent rise and decay times were investigated, and a detailed analysis of the relevant recombination and transport mechanisms under high-temperature conditions was conducted. By achieving high-performance and stable operation of β-Ga2O3 PDs at 800 K, this study provides prospects for the application of β-Ga2O3 PDs in harsh environments.