Performance Of Photodetectors Research Articles

Te2-Regulated Black Arsenic Phosphorus Monocrystalline Film with Excellent Uniformity for High Performance Photodetection.

Two-dimensional (2D) black arsenic phosphorus (b-AsP) material has been attracting considerable attention for its extraordinary properties. However, its application in large-scale device fabrication remains challenging due to the limited scale and irregular shape. Here, we found the special effect of Te2 upon growth of b-AsP and developed a novel Te2-regulated steady growth (Te-SG) strategy to obtain high-quality b-AsP single crystal. The large-scale b-AsP single crystal sheet with its full width at half-maximum (FWHM) being ≤0.05° was achieved for the first time. The b-AsP monocrystalline film with atomic-level flat surface was further fabricated by laser, which exhibits outstanding self-powered characteristics under various light illumination, including low dark current and peak room-temperature detectivity of 8.5 × 1010 cm Hz1/2 W-1. The excellent uniformity was also revealed through a large-plane b-AsP photodetector. This work paves a new way for the application of high-performance electronics and optoelectronics based on b-AsP.

Effect of Deposition Temperature on the Characteristics of Ga2O3 Films Grown on Flexible Mica and the Performance of Corresponding Photodetectors

Effect of Deposition Temperature on the Characteristics of Ga₂O₃ Films Grown on Flexible Mica and the Performance of Corresponding Photodetectors

Enhanced performance and long-term stability of 2D photodetectors through hexagonal boron nitride encapsulation

Two-dimensional (2D) semiconductor materials, such as molybdenum disulfide (MoS2), demonstrate considerable potential for optoelectronic applications, largely due to their atomic thickness, tunable bandgap, and capacity for heterostructure integration. Nevertheless, the development of 2D photodetectors that can achieve high responsivity, a fast response time, and long-term stability remains a significant challenge. The present study is a systematic investigation of the effects of top and bottom encapsulation with hexagonal boron nitride (h-BN) on the performance and stability of 2D photodetectors. By employing a dry transfer process to fabricate a high-quality h-BN/MoS2/h-BN structure, we provide effective protection against environmental degradation. The encapsulated devices exhibited a responsivity increase of one to two orders of magnitude under 532 nm laser illumination, in comparison to those without encapsulation. Additionally, the rise and decay times were markedly reduced, by approximately two orders of magnitude, from 0.538 and 3.43 ms to 23.1 and 99.6 μs, respectively. Moreover, the devices demonstrated sustained performance over a 60-day storage period, with response times remaining faster than pre-encapsulation levels. This study highlights the potential of h-BN encapsulation for enhancing both the performance and stability of 2D photodetectors, advancing the development of more reliable optoelectronic devices.

Chalcogenide perovskites: enticing prospects across a wide range of compositions and optoelectronic properties for stable photodetector devices

Abstract Photodetectors are indispensable components of many modern light sensing and imaging devices, converting photon energy into processable electrical signal through absorption, carrier generation and extraction using semiconducting thin films with appropriate optoelectronic properties. Recently, metal halide perovskites have demonstrated groundbreaking photodetector performance due to their exceptional properties originating from their perovskite structure. However, toxicity and stability remain challenges for their large-scale applications. Inspired by the perovskite structure, intense investigation in search of highly stable, non-toxic and earth abundant materials with superior optoelectronic features has led to the discovery of chalcogenide perovskites (CPs). These are unconventional semiconductors with the formula ABX3, where A and B are cations and X is a chalcogen, which covers the compounds with the corner sharing perovskite structures of type II-IV- VI3 compounds (II = Ba, Sr, Ca, Eu; IV = Zr, Hf; VI = S, Se) and III1-III2-VI3 compounds (III1 and III2 = Lanthanides, Y, Sc; VI = S, Se). The increased coordination and ionicity in these compounds contribute to their excellent charge transport properties and exceptionally high optical absorption coefficient (> 105 cm−1). The present review encompasses theoretical analysis that provides electronic band structures and the orbital contributions that support the excellent optoelectronic properties. Furthermore, the challenging thin film deposition, characterizations, and their application in photodetection focusing on BaZrS3-which is the most studied one, are ascribed. Additionally, we suggest prospects that can bring out the true potential of these materials in photodetection and photovoltaics.

High-performance solar-blind ultraviolet photodetector arrays based on two-inch ϵ-Ga2O3 films for imaging applications

Abstract To achieve high-quality solar-blind imaging applications based on ultrawide bandgap semiconductor photodetectors, it is crucial to fabricate highly uniform wafer-scale films. In this work, we demonstrate the fabrication of exceptionally uniform two-inch ε-Ga2O3 thin films on sapphire substrates using an off-axis pulsed laser deposition method. The two-inch ε-Ga2O3 films exhibit remarkable uniformity across key parameters, including thickness, crystalline quality, bandgap, and surface roughness, with an inhomogeneity ratio less than 5%. Additionally, these films are preferentially oriented along the (001) crystal plane. At 20 V bias, the individual ε-Ga2O3 photodetector demonstrates outstanding solar-blind ultraviolet (UV) photodetection performance, with a responsivity of 52.77 A/W at 240 nm, an external quantum efficiency of 2.7×104%, a dark current of 5.5×10-11 A and a UV–visible rejection ratio of 1.2×104. Furthermore, the 10×10 photodetector arrays fabricated on two-inch ε-Ga2O3 films exhibit highly uniform photodetection performance, with photocurrent deviations remaining within one order of magnitude and a maximum standard deviation of ~8%. High-contrast optical imaging of the letters of “NIMTE” is successfully achieved using the 10×10 photodetector array detector. This work provides valuable insights for fabricating wafer-scale uniform ε-Ga2O3 films and achieving high-quality solar-blind UV imaging applications.

Partial Substitution of Copper with Silver in Cu2ZnSnS4: An Efficient Strategy to Boost the Performance of Self-Powered Broadband Photodetectors in Superstrate Configuration.

Self-powered broadband photodetectors (SPBPDs) hold great potential for next-generation optoelectronic applications, but their performance is often limited by interface defects that impair charge transport and increase recombination losses. In this work, we report the enhancement of the photodetection efficiency of SPBPDs by partially substituting copper (Cu) with silver (Ag) in kesterite Cu2ZnSnS4 (ACZTS) thin films. Varying Ag concentrations (0%, 2%, 4%, 6%) are incorporated into the CZTS layer, forming a TiO2/ACZTS heterojunction in superstrate configuration fabricated via a low-cost sol-gel spin-coating technique with low-temperature open air annealing avoiding conventional postdeposition sulfurization or selenization. Photodetection performance varied significantly with Ag content in CZTS layer, where optimal performance is observed for 4% Ag doping. Under the simulated solar spectrum (100 mW/cm2), the TiO2/4% ACZTS device demonstrates superior performance with an ON/OFF ratio of 6.0 × 102, a photoresponsivity of 0.42 mA/W, and a detectivity of about 2.5 × 109 Jones. In contrast, under 405 nm incident radiation, the device performance improves significantly, achieving an ON/OFF ratio of approximately 4.6 × 103, a photoresponsivity of around 63.9 mA/W, and a detectivity of about 4.8 × 1011 Jones which are the highest reported values observed for CZTS-based single-junction superstrate SPBPDs without a crystalline silicon wafer. Ag doping effectively reduces interface defects and enhances carrier dynamics, as evidenced by capacitance-voltage (C-V) and drive-level capacitance profiling (DLCP) measurements of the fabricated heterojunction. This approach offers a novel strategy for enhancing SPBPD performance through partial cation substitution, paving the way for advanced photodetectors in diverse optoelectronic applications.

Elevating Red and Near-Infrared Detectivity With CsSnI3 Perovskite Photodetectors Featuring GO and PCBM as Charge Transport Layers.

This study focuses on enhancing the performance of photodetector through the utilization of inorganic perovskite material. It emphasizes that the unique properties of perovskite materials contribute to the superior performance of the photodetector. The focus is on the design and enhancement of CsSnI3-based photodetector having graphene oxide (GO) and PCBM as charge transport layer, analysing their potential for improved operation. The design process involves a series of optimizations to the device layers, particularly the absorber layer's thickness and defects, which is critical for enhanced efficiency. The designed photodetector exhibits a better responsivity and detectivity in red and near infrared region and maximum responsivity of 0.68 A/W and detectivity of 9 × 1012 Jones. The SCAPS-1D tool is employed to facilitate the design analysis, enabling the fine-tuning of the device parameters. The findings highlight the effectiveness of perovskite materials in boosting photodetector performance.

Improved performance of solar blind ultraviolet photodetectors by spatial ALD Zn-doped Ga2O3 film and post-annealing

Improved performance of solar blind ultraviolet photodetectors by spatial ALD Zn-doped Ga2O3 film and post-annealing

Simulation of high signal-to-noise ratio resonant photodetector for homodyne measurement and its verification.

In this paper, two models for simulating the shot noise and electronic noise performances of resonant photodetectors designed for homodyne measurements are presented. One is based on a combination of a buffer and a low-noise amplifier, and the other is based on an operational amplifier. Through the comparisons between the numerical simulation results and the experimentally obtained data, excellent agreements are achieved, which show that the models provide a highly efficient guide for the development of a high signal-to-noise ratio (SNR) resonant photodetector. Furthermore, we demonstrate a high SNR resonant photodetector for homodyne measurements at the 147MHz optical sideband, achieving a 20.8 dB SNR of the shot noise to the electronic noise with a 2 mW optical signal input, utilizing a combination of a buffer and a low-noise amplifier. Concurrently, we have obtained another resonant photodetector at the 1.14GHz optical sideband, which exhibits a 13 dB SNR based on an operational amplifier.

Enhanced two-photon absorption in hydrothermally synthesized La2O6Te nanorods for visible light photodetection.

In the present study, lanthanum oxytellurate (LOT) samples with varying La : Te ratios are successfully synthesized using a simple hydrothermal method that has enormous advantages. The prepared samples crystallize in a La2O6Te composite phase with an orthorhombic crystal system. A nanorod-like morphology is observed for each sample, and the presence of constituent elements is verified from EDX results. Chemical compositions and their oxidation states are obtained from XPS studies. Optical studies of the materials demonstrated band gap values between 2.65 and 2.78 eV, confirming the LOT samples' semiconducting nature. Broad photoluminescence (PL) spectra with peaks ranging between 650 and 750 nm were observed, and a red shift occurred by increasing the Te concentration in the samples. Overall, the samples exhibit good photoresponse characteristics under dark and light conditions with high Ion/Ioff ratios and sensitivity values. These parameters confirm the potential of LOT materials to stand out as an alternative for susceptible and effective photodetector devices. Among the samples, LOT-2 showed 10.64 μA W-1 responsivity, 5.8 × 107 Jones of detectivity, and a rise and fall time of 16.25 and 23.13 s, respectively, which was the best photodetection performance compared to the other two samples. Results from the nonlinear optical (NLO) Z-scan study demonstrated the RSA behavior and valley-peak configuration with positive n2 values corresponding to the self-focusing effect. The NLO characteristics of the materials are governed by the two-photon absorption (2PA) mechanism. Here, the LOT-2 sample displayed comparatively better results than the other two. The third-order nonlinear optical NLO susceptibility χ(3) values suggest that LOT materials have the potential to become a new candidate for various NLO applications in the coming days.

High Performance of Cs2AgBiBr6 Perovskite-based Photodetectors by Adding DEAC.

Perovskite-based photodetectors (PDs) are broadly utilized in optical communication, non-destructive testing, and smart wearable devices due to their ability to convert light into electrical signals. However, toxicity and instability hold back their mass production and commercialization. The lead-free Cs2AgBiBr6 double perovskite film, promised to be an alternative, is fabricated by electrophoretic deposition (EPD), which compromises film quality. Herein, we improved the quality of the Cs2AgBiBr6 films and the performance of PDs by adding N-acetylethylenediamine (DEAC) to Cs2AgBiBr6 perovskite precursor for EPD, in which the ligand DEAC provides a pair of lone electrons to Bi3+, forming coordinate covalent bonds. The optimized PDs have high detectivity, up to 4.4×1012 Jones, and high stability in the air. The high-performance, flexible Cs2AgBiBr6 perovskite PDs were fabricated on this basis, it also achieved the detectivity up to 3.2×1012 Jones with excellent bending cycle stability. These results propose a feasible approach to improving the crystallization of double perovskite thin films by introducing ligands during the EPD process. Furthermore, they demonstrate enhanced optoelectronic performance, indicating that this method is also applicable to halide perovskites, offering an effective strategy to improve their film quality.

Ho doping-induced ferroelectric polarization enhances UV photodetector performance of YbMnO3

Ho doping-induced ferroelectric polarization enhances UV photodetector performance of YbMnO3

Laser pulse tuning for optimized photodetector performance in CsPbI3/Si heterojunctions

Laser pulse tuning for optimized photodetector performance in CsPbI3/Si heterojunctions

Tellurium/Bismuth Selenide van der Waals Heterojunction for Self-Driven, Broadband Photodetection and Polarization-Sensitive Application.

Broadband detection technology is crucial in the fields of astronomy and environmental surveying. Two dimensional (2D) materials have emerged as promising candidates for next-generation broadband photodetectors with the characteristics of high integration, multi-dimensional sensing, and low power consumption. Among these, 2D tellurium (Te) is particularly noteworthy due to its excellent mobility, tunable bandgap, and air stability. However, the performance of the Te-based photodetector has been hindered by high dark current and cut-off wavelength limitations associated with its intrinsic bandgap. Here, the Te / bismuth selenide (Bi2Se3) van der Waals (vdWs) p-n heterojunction with a clean interface and type-II band alignment, designed to address these challenges are presented. The Te/Bi2Se3 heterojunction photodetectors demonstrate an ultra-broadband photodetection range from Ultraviolet (UV)to Mid-infrared (MIR) (365 nm-4.3µm) and a high responsivity up to 880mA W-1 at 1550nm under zero bias. Moreover, benefiting from the anisotropy crystal structure of Te, the photodetector shows an obvious polarization-sensitive photoresponse and enormous potential in optical communication and polarization imaging. This work hereby provides significant insight into low-powered, high-performance, and broadband vdWs heterojunction photodetectors and their functional applications.

Enhanced Performance of Sn-Based Perovskite Photodetectors Through Double-Sided Passivation for Near-Infrared Applications.

The development of high-performance Sn-based perovskite photodetectors is presented with double-sided passivation using large alkylammonium interlayers of PEAI and BDAI₂. This dual passivation strategy, applied to the top and bottom of FASnI₃ films, effectively improves film quality by reducing defect density, enhancing carrier mobility, and minimizing non-radiative energy losses at the interfaces. At 720nm, the photodetectors demonstrate a responsivity of 0.37AW-1, a detectivity of 6.12×10¹3 Jones, and an external quantum efficiency (EQE) of 65.60%, with a rapid response time of 9 µs. Additionally, at 850nm, the detectivity reaches as high as 3.27 × 10¹3 Jones. Furthermore, the device demonstrated a low 1/f noise of 1.21 × 10⁻¹⁵ AHz⁻⁰.⁵ at 10Hz. Transient photocurrent (TPC) and transient photovoltage (TPV) measurements revealed a significant increase in charge recombination lifetime (τe) and improved charge transfer efficiency. These results showcase the potential of Sn perovskite photodetectors for near-infrared applications, including autonomous vehicles, biometric recognition, and biomedical treatments.

Correction: Engineering surface state density of monolayer CVD grown 2D MoS2 for enhanced photodetector performance

Correction: Engineering surface state density of monolayer CVD grown 2D MoS2 for enhanced photodetector performance

First-principles study of electron dynamics of MoS2 under femtosecond laser irradiation from deep ultraviolet to near-infrared wavelengths.

Time-dependent density functional theory was employed to investigate the electron dynamics of MoS2 following femtosecond pulse irradiation. The study concerned the effects of laser wavelength, intensities, and polarization and elucidated the ionization mechanisms across the intensity range of 1010-1014 W/cm2. As laser intensity increases, MoS2 irradiated with an infrared (IR) laser (800nm) deviates from single-photon absorption at lower intensities compared to that subjected to an ultraviolet (UV) laser (266nm), and nonlinear effects in the current arise at lower intensities for the 800nm laser. At a wavelength of 266nm, MoS2 irradiated with an a-axis polarized laser deposited more energy and generated more electron-hole pairs compared to c-axis polarization. Rate equations were used to estimate the total number of excited electrons in MoS2 and the corresponding plasma frequency. Simulation results indicate that the damage threshold of the UV laser is higher than that of the IR laser, which contradicts the experimental results. This outcome suggests that the mechanism of material damage induced by the UV femtosecond laser near the damage threshold is independent of optical breakdown. The findings of this research are significant for enhancing the performance of MoS2-based photodetectors and optimizing their stability and reliability in high-power, short-wavelength laser applications.

Dual‐Sided Field Effect Passivation for Efficient and Stable Quasi‐2D Ruddlesden‐Popper Perovskite Photodetector

AbstractThe nonradiative recombination presented at the quasi‐2D (Q‐2D) Ruddlesden–Popper perovskite surface/interface limits the overall performance of perovskite photoelectric devices. Here, a dual‐sided field effect passivation (FEP) strategy to reduce nonradiative recombination is reported. By inserting high/low work function dielectric layers between perovskite layer and hole/electron transport layers, the trap state density of perovskite layer is effectively reduced, resulting in a longer carrier lifetime. Besides, the carrier dynamics and the synergistic mechanism of chemical passivation (CP) and FEP are clarified in detail. The interfacial polarization caused by the work function difference between different layers prevents Shockley–Read–Hall (SRH) recombination loss of photogenerated electrons/holes and improves interfacial charge transport. Benefiting from it, the passivated photodetector performance has been improved effectively, achieving a dark current of 9.62 × 10−11 A, a linear dynamic range (LDR) width of 171.4 dB, and an ultra‐fast response time low to 430 ns, which are currently the highest reported detection indicators in the Q‐2D perovskite photodetectors. In addition, the dual‐sided field effect passivated intercalation inhibits perovskite decomposition and greatly improves the environmental stability. In future, exploring the synergistic effect of FEP and CP materials for perovskite films is one of the development directions for studying efficient and stable perovskite photoelectric devices.

Tunable WSe2-MoSe2 Lateral Heterojunction Photodetector Based on Piezoelectric and Flexoelectric Effects.

Two-dimensional transition metal dichalcogenides (TMDs) with piezoelectric effects are ideal materials for future wearable devices. While enhancing the piezoelectric performance by forming vertical heterojunctions, shortcomings such as contamination at the heterojunction interface and limited built-in electric field width have been noticed. In this work, a lateral heterojunction of monolayer WSe2-MoSe2 with type-II band alignment was employed to amplify the electromechanical optoelectronic efficiency. The considerable built-in field width (BFW) in the lateral heterojunction facilitates rapid separation of carriers. The lattice mismatch induced a flexoelectric effect during the lateral heterojunction growth. The flexoelectric and piezoelectric effects under external strain can regulate the photodetector performance of the device. Under the compressive strain of -0.93%, the photocurrent increased 9.1 times compared to the tensile strain of 0.47%. Flexoelectric effect can reduce the dark current under no external strain. This work reveals the roles of flexoelectric and piezoelectric effects in enhancing photoelectric conversion, suggesting lateral heterojunction devices may be applied in the field of flexible low-light detection.

Improved photoresponse performance of self-powered solar-blind UV photodetectors based on n-Si/n-Ga2O3/p-Li:NiO dual-junction

The solar-blind photodetectors (SBPDs) based on the wide-bandgap semiconductor gallium oxide (Ga2O3) exhibit significant potential for applications in military, civilian, and medical fields. Although multiple structural designs of Ga2O3-based SBPDs have been proposed, their performance typically falls short of commercial standards. However, the photoresponse speed of most self-powered PDs decreases rapidly in the solar-blind region. To address this issue, we first prepared high-quality single-crystal β-Ga2O3 films using RF magnetron sputtering, which exhibit an average transmittance exceeding 85% across the 400–800 nm range and possess a relatively smooth surface. Subsequently, a superior performance self-powered SBPD of vertical structure of n-Si/n-Ga2O3/p-Li:NiO dual-junction was fabricated, which possesses a responsivity of 0.18 mA/W, a photo-to-dark current ratio of 395, rapid rise/decay times of 132/148 ms, and a specific detectivity of 1.57 × 109 Jones at 0 V bias under 254 nm illumination. The photocurrent of the device fully recovered to its initial level after experiencing changes in ambient temperature [from room temperature (RT) to 100 °C and back to RT], demonstrating robust stability in harsh environments. In addition, the valence band structures of p-Li:NiO and n-Ga2O3 were investigated in detail using XPS, and the working mechanism of the devices was analyzed based on the Fermi level alignment. The excellent performance of PDs can be attributed to the increased depletion layer width, which generates more photogenerated carriers. Additionally, the separation and transmission of photo-induced carriers are enhanced by the superposition of a double built-in electric field. Our strategy offers a promising approach for achieving high-performance Ga2O3-based photovoltaic PDs.