Photodetectors Research Articles

Self-powered Schottky barrier photodetector with high responsivity based on homoepitaxial Ga2O3 films by MOCVD

Abstract Ga2O3 is a fast-developing wide band semiconductor for solar-blind ultraviolet (SBUV) photodetectors (PDs) applications. The heterojunction self-powered PDs fabricated from heteroepitaxial Ga2O3 films currently have low responsivity and response speed. In this work, we fabricated Schottky barrier PDs based on homoepitaxially grown high quality Ga2O3 films, which show high performance manifested in high responsivity at different bias voltages. In particular, the device achieves a responsivity of 90.3 mA/W, a photo-to-dark current ratio of 3.2×104 and a detectivity of 3.8×1013 Jones at 0 V. In addition, a response time of superior to 5 ms is achieved. The results demonstrate the advantages of homoepitaxial Ga2O3 films in the field of high-performance devices.

ε-InSe-based heterojunction photodetector and its performance modulation by growth pressure

Indium selenide (InSe) is a III-VI semiconductor with excellent optoelectronic properties that has been widely studied. In this work, a series of InSe films are successfully prepared by pulsed laser deposition (PLD) under different growth pressures ranging from 0.1 to 10 Pa. The structural characterization shows that the InSe films have a ε phase structure with the best film quality obtained at 1 Pa. The photoresponse of ε-InSe/Si heterojunction photodetectors (PDs) is thoroughly investigated under illumination of different laser wavelengths and powers. The results demonstrate that the photoresponse is strongly dependent on the growth pressure of the InSe films, with the optimal performance achieved at a growth pressure of 1 Pa. The ε-InSe/Si heterojunction PD at 1 Pa exhibits an ultra-broadband photoresponse spanning from 360 to 1064 nm with the best responsivity (R) of 6.68 × 10-2 A/W, detectivity (D) of 6.51 × 1010 Jones, external quantum efficiency (EQE) of 12.4 %, and response times of ∼ 35 ms. The influence of growth pressure on the PD performance can be attributed to its effects on the structural and morphological properties of the InSe film. This work provides a promising approach for the preparation of high-performance InSe-based optoelectronic devices.

Self-Driven Perovskite/Organic Quasi-Tandem Photodetectors Operating in Both Narrowband and Broadband Regimes.

Dual-band photodetectors (PDs) have attracted extensive research attention due to their great potential for diverse and refreshing application scenarios in full-color imaging, optical communication, and imaging detection. Here, a self-driven dual-band PD without filters and other auxiliary equipment to achieve a narrowband response in Mode 1 and a broadband response in Mode 2 was designed based on carrier-selective transmission narrowing (CSTN). The polymer material poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), which has the appropriate energy level, was selected to be the carrier-selective transmission layer. In Mode 1, the dual-band PD exhibits a near-infrared (NIR) narrowband response in 750-900 nm, which indicates a responsivity of 360 mA/W, a full-width at half-maximum (fwhm) of 81 nm, and a specific detectivity (D*) of 7.49 × 1010 Jones at 810 nm. Simultaneously, in Mode 2, the dual-band PD exhibits a UV-visible-NIR broadband responsivity of 180 mA/W and a specific detectivity (D*) of 3.8 × 1010 Jones at 520 nm. Our study provides a reliable idea for the commercial applications of dual-function photodetectors.

Self‐Powered Cs3Bi2I9/ZnO Heterojunction Photodetector with Dual‐Band Photoresponse

AbstractCs3Bi2I9/ZnO heterostructures are constructed by the growth of Cs3Bi2I9 layer onto the spin‐coated ZnO films by a modified antisolvent recrystallization method, a series of Cs3Bi2I9/ZnO heterojunction photodetectors (PDs) with varied growth times of Cs3Bi2I9 layer are fabricated. The construction of Cs3Bi2I9/ZnO heterojunction contributes to their improved photoelectric performance compared to ZnO‐based PD, and the Cs3Bi2I9 layer thickness plays an important role in tuning the photoelectric performance of these PDs. At 405 nm and 0 V bias, the optimized 6‐Cs3Bi2I9/ZnO PD generates a high photocurrent of −3.03 µA, a medium on/off ratio of 144.3, and a short response time of 16.4 ms/16.8 ms. It also exhibits superior dual‐band self‐powered photoresponse with two responsivity and detectivity peaks at 380 nm in the UV region and at 430 nm in the visible light region. At 380 nm, this PD presents the highest responsivity of 33.2 mA W−1 and detectivity of 1.07 × 1010 Jones. It is believed that the optimized growth of the Cs3Bi2I9 layer generates a depletion layer with suitable thickness near the interface, and the as‐promoted charge‐carrier separation and transport result in improved self‐powered properties. The rational construction of perovskite‐based heterojunction has proved as an efficient way to achieve self‐powered photodetection.

Improved UV Photoresponse Performance of ZnO Nanowire Array Photodetector via Effective Pt Nanoparticle Coupling.

Ultraviolet (UV) photodetectors (PDs) based on nanowire (NW) hold significant promise for applications in fire detection, optical communication, and environmental monitoring. As optoelectronic devices evolve towards lower dimensionality, multifunctionality, and integrability, multicolor PDs have become a research hotspot in optics and electronic information. This study investigates the enhancement of detection capability in a light-trapping ZnO NW array through modification with Pt nanoparticles (NPs) via magnetron sputtering and hydrothermal synthesis. The optimized PD exhibits superior performance, achieving a responsivity of 12.49 A/W, detectivity of 4.07 × 1012 Jones, and external quantum efficiency (EQE) of 4.19 × 103%, respectively. In addition, the Pt NPs/ZnO NW/ZnO PD maintains spectral selectivity in the UV region. These findings show the pivotal role of Pt NPs in enhancing photodetection performance through their strong light absorption and scattering properties. This improvement is associated with localized surface plasmon resonance induced by the Pt NPs, leading to enhanced incident light and interfacial charge separation for the specialized configurations of the nanodevice. Utilizing metal NPs for device modification represents a breakthrough that positively affects the preparation of high-performance ZnO-based UV PDs.

Synergistic Effect of Ionic Liquid and Embedded QDs on 2D Ferroelectric Perovskite Films with Narrow Phase Distribution for Self-Powered and Broad-Band Photodetectors.

2D layered metal halide perovskites (MHPs) are a potential material for fabricating self-powered photodetectors (PDs). Nevertheless, 2D MHPs produced via solution techniques frequently exhibit multiple quantum wells, leading to notable degradation in the device performance. Besides, the wide band gap in 2D perovskites limits their potential for broad-band photodetection. Integrating narrow-band gap materials with perovskite matrices is a viable strategy for broad-band PDs. In this study, the use of methylamine acetate (MAAc) as an additive in 2D perovskite precursors can effectively control the width of the quantum wells (QWs). The amount of MAAc greatly affects the phase purity. Subsequently, PbSe QDs were embedded into the 2D perovskite matrix with a broadened absorption spectrum and no negative effects on ferroelectric properties. PM6:Y6 was combined with the hybrid ferroelectric perovskite films to create a self-powered and broad-band PD with enhanced performance due to a ferro-pyro-phototronic effect, reaching a peak responsivity of 2.4 A W-1 at 940 nm.

Interfacial passivation by using an amorphous hafnium oxide thin layer toward improved CH3NH3PbI3/Si heterojunction photodetectors

In this paper, we reported the fabrication of improved CH3NH3PbI3/Si heterojunction photodetectors (PDs) achieved by passivating the interfacial defects by a low-temperature atomic layer deposition-grown thin amorphous HfO2 layer. The results suggested that the HfO2 thin layer effectively passivated the surface defects of Si and slightly improved the qualities of CH3NH3PbI3 thin films in terms of increasing the grain sizes. Current–voltage measurements suggested that the HfO2 thin layer suppressed interfacial Shockley–Read–Hall recombination, which decreased the dark current and simultaneously increased the photocurrent. However, a thick HfO2 layer resulted in a decrease in the photocurrent because of the insulting nature of HfO2. A champion performance was obtained by employing a 5 nm HfO2 layer, where the responsivity and detectivity were 0.6 mA/W and 8.0 × 1010 Jones, respectively, which are two times and four times as high as those PDs without the HfO2 layer. The results will provide a simple strategy for improving the performance of perovskite/Si heterojunction PDs in the future.

Negative photoconductivity and high detectivity in Ba-doped ZnO UV photodetectors

This research investigates the effects of barium (Ba) doping the photoelectric properties of zinc oxide (ZnO) nanoparticles (NPs) to explore their potential applications in optoelectronic devices.Photocurrent experiments reveal intriguing negative photoconductivity (NPC) behavior in Ba:ZnO based UV photodetectors (PDs).Moreover, the exploration of UV PD performance reveals rise and fall times of approximately 8.26s and 8.72s, respectively, under a -1V external bias.Our fabricated device shows higher detectivity about 1.33×1016 Jones and external quantum efficiency exceeding 100 %, compared to other PD. The analysis of transient currentsuggests the existence of two kinds of defects contributing to NPC. Through an investigation of the noise density, exponents γ ranging between −2.048 and −1.76 were determined, substantiating the hypothesis that the observed noise originates from a distribution of defects. Overall, these results underscore the potential of Ba:ZnO NPs for high-performance devices compared to conventional ZnO-based PDs.

Low dark current Sb-based short-wavelength infrared photodetector

We have theoretically and experimentally demonstrated the feasibility of achieving ultra-low dark current in CpBnn type detectors based on a double-barrier InAs/GaSb/AlSb type-II superlattice. By employing a structure that separates the absorption region and depletion region, the diffusion, recombination, tunneling, and surface dark currents of the photodetector (PD) have been suppressed. Experimental validation has shown that a detector with a diameter of 500 µm at a bias voltage of −0.5 V exhibits a dark current density of 2.5 × 10−6 A/cm2 at the operating temperature of 300 K. The development of PD with low dark current has paved the way for applications with high demands for low noise in the fields of gravitational wave detection and astronomical observation.

High ultraviolet gain in Ga2O3/ZnO heterojunction photodetector based on MSM structure

Amorphous Ga2O3 (a-Ga2O3) has attracted extensive attention due to its simple preparation process and low cost, but the extension of photoelectron lifetime caused by the trap state inhibits the responsiveness of a-Ga2O3 photodetector (PD), and how to improve the ultraviolet (UV) gain of a-Ga2O3 based PD is still a challenge. In this study, an a-Ga2O3/ZnO heterojunction PD based on metal-semiconductor-metal (MSM) structure was designed and fabricated by radio frequency magnetron sputtering (RFMS), and a high-concentration electron transport channel was formed by using carrier multiplication and specific band structure in the high-field region of MSM structure, which achieved high optical gain and extraordinary optical detection ability. In the UVC-UVA band, the device has a peak responsivity of 1.59 A W−1 and a high light-dark ratio, EQE and D* of 1×104, 647 % and 3.6×1012 Jones under 5 V, respectively. In particular, compared to ZnO PD and a-Ga2O3 PD, the responsivity of the device is improved by a factor of 21 and 90, respectively. This study provides a new and effective method for the significant improvement of a-Ga2O3 based UV photoelectric detection performance.

Reconfigurable MIMO-based self-powered battery-less light communication system

Simultaneous lightwave information and power transfer (SLIPT), co-existing with optical wireless communication, holds an enormous potential to provide continuous charging to remote Internet of Things (IoT) devices while ensuring connectivity. Combining SLIPT with an omnidirectional receiver, we can leverage a higher power budget while maintaining a stable connection, a major challenge for optical wireless communication systems. Here, we design a multiplexed SLIPT-based system comprising an array of photodetectors (PDs) arranged in a 3 × 3 configuration. The system enables decoding information from multiple light beams while simultaneously harvesting energy. The PDs can swiftly switch between photoconductive and photovoltaic modes to maximize information transfer rates and provide on-demand energy harvesting. Additionally, we investigated the ability to decode information and harvest energy with a particular quadrant set of PDs from the array, allowing beam tracking and spatial diversity. The design was explored in a smaller version for higher data rates and a bigger one for higher power harvesting. We report a self-powering device that can achieve a gross data rate of 25.7 Mbps from a single-input single-output (SISO) and an 85.2 Mbps net data rate in a multiple-input multiple-output (MIMO) configuration. Under a standard AMT1.5 illumination, the device can harvest up to 87.33 mW, around twice the power needed to maintain the entire system. Our work paves the way for deploying autonomous IoT devices in harsh environments and their potential use in space applications.

Recent Advances of Photodetection Technology Based on Main Group III–V Semiconductors

AbstractThe rapid advancement of main group III–V nanomaterials endows photodetectors (PDs) with enhanced performance. At present, various III–V nanomaterials are systematically investigated, whereof III–V semiconductors have attracted a successively increased attention that calls for a comprehensive summary which also can define the state‐of‐art for their further development. Herein, this work systematically introduces and discusses key aspects of the field. First, the advanced strategies for the preparation of III–V semiconductor materials and the device structures of the subsequent PDs based on these materials, pristine and doped, are addressed. The focus is then turned to their performance under the irradiation of various wavelengths, separately summarizing and comparing the photodetection properties under infrared, UV and visible light. Finally, challenges and future perspectives of III–V semiconductor‐based PDs are highlighted. This review enlightens the development of III–V semiconductor‐based PDs, and their extended applications for optoelectronic devices in general.

A visible light positioning system for coal mine personnel based on convolutional recurrent neural network

Visible Light Positioning (VLP) technology exhibits promising potential for underground coal mine positioning. While numerous studies have explored VLP in indoor environments, attention to VLP systems for underground mines still needs to be improved. In this paper, based on the traditional indoor visible light communication channel model, the effects of unique features on VLP, such as irregular walls, inclined and rotating receiving ends, and coal dust particles in underground mines, are considered and modeled in detail. In order to improve the accuracy and reliability of personnel VLP in complex mine environments, this paper proposes a deep-learning-based VLP system for underground personnel in coal mines, which consists of two LEDs and four photodetectors (PDs), where the four PDs are mounted on miners' helmets, in conjunction with the actual mine environment. Due to environmental factors and noise, there are apparent spatio-temporal characteristics in the received signal strength of the PDs. Therefore, the system adopts a convolutional recurrent neural network (CRNN) for feature extraction. In the experimental phase, the method's average localization error was 11.24 cm, with 90% of the localization errors within 20.4 cm. The experimental results show that the system has high positioning accuracy and meets the requirements of personnel positioning in underground mines.

Numerical evaluation and optimization of high sensitivity Cu2CdSnSe4 photodetector

Copper cadmium tin selenide (Cu2CdSnSe4) based photodetector (PD) has been explored with the solar cell capacitance simulator (SCAPS-1D). Herein, cadmium sulfide (CdS) and molybdenum disulfide (MoS2) are used as a window and back surface field (BSF) layers, respectively. The physical attributes, such as width, carrier density and bulk defects have been adjusted to attain the optimal conditions. In an optimized environment, the performance parameters of the Cu2CdSnSe4 (CCTSe) PD e.g. open circuit voltage (VOC), short circuit current (JSC), responsivity, and detectivity are determined as 0.76 V, 45.57 mA/cm2, 0.72 A/W and 5.05 × 1014 Jones, respectively without a BSF layer. After insertion of the BSF layer, the performance of the CCTSe PD is significantly upgraded because of the production of high built-in potential which rises the magnitude of VOC from 0.76 V to 0.84 V. For this reason, the responsivity and detectivity of CCTSe PD are also grows with the value of 0.84 A/W and 2.32 × 1015 Jones, respectively that indicate its future potential.

A Photolithography-Free Fabrication Strategy for Perovskite Photodetector Array with High-Security Imaging Application.

Metal halide perovskites have attracted significant attention for high-performance and cost-effective photodetector (PD) arrays in recent years. Traditional perovskite photodetector arrays typically rely on planar structure and photolithography, which limit resolution and involve complex, costly processes. To address these challenges, an innovative, lithography-free fabrication strategy is proposed utilizing direct laser writing ablation and a surface energy-assisted selective growth process. A 10×10 self-powered perovskite photodetector array is demonstrated with a vertical cross-bar structure fabricated on a laser-ablated textured Indium-Tin Oxide (ITO) substrate which improves the device performance. The device exhibits a fast photoresponse and effective imaging capability. Moreover, the intrinsic physical disorder and randomness of perovskite provide highly secure entropy sources, making the photodetector array suitable for physical unclonable function (PUF) devices. This method offers a promising opportunity for simplifying the fabrication process, enhancing manufacturability, and advancing the application of perovskite PD arrays in secure imaging systems.

Alloy engineered cryotronically stable polymorphic strained photo detector functionalized by palladium enriched tin diselenide nanosheets

Scientists experience formidability in developing an advanced materials capable to withstand extreme environmental circumstances without sacrificing its fundamental properties. In this realm, solid-state devices utilizing 'metal dichalcogenide' materials offer significant advantages for cryogenic purposes, but rarely explored. In this study, thin film photodetectors (TFPDs) based on meta-materials of PdxSn1−xSe2 (x=0.0, 0.2, 0.5) nanosheets are introduced. Nanosheets are extracted from bulk via sonochemical exfoliation to fabricate TFPDs. Novel material Pd0.5Sn0.5Se2 grown by 50 % palladium enrichment in SnSe2 exhibits polymorphism comprising structural duality of hexagonal-orthorhombic phases. TFPDs based on PdxSn1−xSe2 (x=0.0, 0.2, 0.5) nanosheets display substantial photoresponse in which TFPD functionalised by Pd0.5Sn0.5Se2 nanosheets portrays superior photodetection. Raman peak demonstrates notable thermal-sensing through blue-shifting and sharpening under cryogenic-temperatures. Surprisingly, Pd0.5Sn0.5Se2 nanosheets based TFPD reveals considerable photodetection, achieving 0.52 mAW−1 responsivity at 10 K cryogenic-temperature. To the best of our knowledge, present investigation surpasses previous reports, highlighting a thin film-based photo detector that represents exceptional responsivity at 10 K cryogenic-temperature reported by us for the first time. As an outcome of present study, a TFPD based on Pd0.5Sn0.5Se2 nanosheets emerges as advanced cryotronic material for designing next-generation cryogenic photonic devices due to its higher steadiness, excellent reproducibility and operational efficiency at cryogenic-temperature of 10 K.

Silicon photomultipliers for future HEP experiments

For the particle identification systems of the future high-energy physics detectors, single-photon sensors with sub-mm granularity, high sensitivity, and mitigation strategy for operation in the neutron-irradiated areas are needed. Silicon photomultipliers are considered a baseline technology because of their high photon detection efficiency, good timing resolution, and low operating voltage compared to those of vacuum-based photo sensors. After neutron irradiation, the dark counts increase dramatically and distort the signal baseline, making the single photons indistinguishable. Although the DCR of different unirradiated SiPMs varies, the devices show very similar rates when irradiated to high doses. In this work, we investigated the performance parameters of FBK NUV-HD-RH UHD-DE 1 mm2 devices and determined the working temperature. We show that the maximum operation temperature for samples irradiated with a fluence of 1012 neq/cm2 is around -100°C.

Expanding the Spectral Responsivity of Photodetectors via the Integration of CdSe/ZnS Quantum Dots and MEH-PPV Polymer Composite.

This study investigates the energy transfer mechanism between the organic polymer poly(2-methoxy-5(2'-ethyl)heroxyphenylenevinylene) (MEH-PPV) and CdSe/ZnS core-shell quantum dots (CdSe/ZnS CSQDs). Additionally, a hybrid ZnO-based photodetector (PD) is fabricated using the composite of MEH-PPV and CdSe/ZnS CSQDs, aiming to gain deeper insights. The combination of MEH-PPV and CdSe/ZnS CSQDs facilitates a broad spectral response in PDs, spanning from the ultraviolet (UV) to the visible range. In particular, PDs with QDs in the composite demonstrate notably excellent photosensitivity to both ultraviolet (UV) light (365 nm) (~5 fold) and visible light (505 nm) (~3 fold).

Calibration-free scheme for frequency response measurement of a Mach–Zehnder modulator with low-frequency detection

This paper presents a novel, to the best of our knowledge, calibration-free scheme for measuring the frequency response of Mach–Zehnder modulation (MZM) using low-frequency detection. An auxiliary MZM1 modulated by a MHz-level electrical signal f1 is utilized to generate a double-sideband optical signal, which is subsequently directed into the device under test (MZM2). The MZM2 is biased at its minimum point and driven by a frequency-swept microwave signal f m . After photoelectric converting, a fixed low-frequency electrical signal f L carrying the frequency response information of the MZM2 is generated. By sweeping f m while extracting the amplitude of f L , the frequency response of the MZM2 free from the response of the photodetector (PD) is thus determined. In the experiment, the frequency response of a commercial MZM is characterized in the frequency range from 0.1 GHz to 20 GHz with a resolution of 50 MHz. The measurement result is consistent with the vector network analyzer swept method. In addition, the new method eliminates errors introduced by the PD and reduces the requirement for a high-bandwidth PD.

112-GBaud mode-division-multiplexing IM-DD transmission beyond net 6.4 Tb/s over weakly coupled FMF for optical interconnections.

Weakly coupled mode-division-multiplexing (MDM) systems based on intensity modulation and direct detection (IM-DD) are a good candidate for further improving the capacity of short-reach optical interconnections. However, restrained by the modal crosstalk of the transmission link and the reception of degenerate mode groups (DMGs) utilizing bandwidth-limited multimode photodetectors (PDs), high-speed MDM IM-DD has encountered a capacity bottleneck. In this Letter, we investigate a high-speed weakly coupled MDM IM-DD transmission system utilizing a degenerate mode diversity receiver scheme adopting high-bandwidth single-mode PDs over a multiple-ring-core (MRC) few-mode fiber (FMF) and a low-crosstalk mode multiplexer/demultiplexer (MUX/DMUX). An MDM IM-DD transmission with four DMGs and eight wavelengths is experimentally demonstrated with 112-GBaud four-level pulse-amplitude modulation (PAM4) and probabilistically shaped PAM8 per lane over 200-m weakly coupled MRC-FMF. To the best of our knowledge, this is the first experimental demonstration of the MDM IM-DD transmission system with up to 112-GBaud baud rate and beyond 6.4-Tb/s net rate. Meanwhile, the experimental results show that the proposed MDM IM-DD transmission link has a superior performance only adopting a low-complexity feedforward equalizer, making it a promising candidate for high-speed optical interconnections.