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As an emerging field, self‐powered photoelectrochemical (PEC) photodetectors have gradually attracted extensive attention thanks to the unique working characteristics of low preparation cost, strong tunability of device performance, and environmental friendliness. However, short absorption wavelength range, low efficiency of visible light utilization, and low responsivity remain challenges for performance improvements. Here, the PEC photodetectors based on the 2D BiVO4/MXene Schottky junction structure, which shows excellent performance with high photocurrent density (≈3.90 mA cm−2 at 0 VSCE under AM 1.5 G, 150 mW cm−2), good responsivity (790.2 mA W−1 under 447 nm), fast response time (tr/tf = 8/14 ms), and long‐term stability (keep 17 000 s and 22 000 cycles) are fabricated. These can be attributed to the built‐in electric field at the BiVO4/MXene Schottky junction interface, which accelerates the transfer of photogenerated electrons and holes, and inhibits interfacial charge recombination. Additionally, the MXene nanosheets improve the absorption of visible‐light‐induced photons on the valence band of BiVO4. These excellent properties show that this work provides a scientific experimental reference for the further development of PEC photodetectors. [ABSTRACT FROM AUTHOR]

Designing efficient narrow-band near-infrared photodetectors integrated on silicon for telecommunications remains a significant challenge in silicon photonics. This paper proposes a novel silicon-based hot-electron photodetector employing Tamm plasmons (Si-based TP-HE PD) for narrow-band near-infrared photodetection. The device combines a one-dimensional photonic crystal (1DPC) structure, an Au layer, and a silicon substrate with a back electrode. Simulation results show that the absorption of the TP device with a back electrode is 1.5 times higher than without a back electrode, due to increased absorption from multiple reflections between the back electrode and the 1DPC structure. Experimentally, the responsivity of the fabricated device reaches 0.195 mA/W at a wavelength of 1400 nm. A phenomenological model was developed to analyze the photoelectric conversion mechanism, revealing reasonable agreement between the theoretically calculated and experimentally measured internal quantum efficiencies. Additional experiments and simulations demonstrate the tunability of the resonance wavelength from 1200 nm to 1700 nm by adjusting structural parameters. The Si-based TP-HE PD shows potential for silicon-based optoelectronic applications, offering the advantages of a simple structure, low cost, and compatibility with silicon photonic integrated circuits. This work represents the first demonstration of a silicon-based hot electron NIR photodetector utilizing Tamm plasmons. [ABSTRACT FROM AUTHOR]

High-sensitivity room-temperature multi-dimensional infrared (IR) detection is crucial for military and civilian purposes. Recently, the gapless electronic structures and unique optoelectrical properties have made the two-dimensional (2D) topological semimetals promising candidates for the realization of multifunctional optoelectronic devices. Here, we demonstrated the in-situ construction of high-performance 1T'-MoTe2/Ge Schottky junction device by inserting an ultrathin AlOx passivation layer. The good detection performance with an ultra-broadband detection wavelength range of up to 10.6 micron, an ultrafast response time of ~ 160 ns, and a large specific detectivity of over 109 Jones in mid-infrared (MIR) range surpasses that of most 2D materials-based IR sensors, approaching the performance of commercial IR photodiodes. The on-chip integrated device arrays with 64 functional detectors feature high-resolution imaging capability at room temperature. All these outstanding detection features have enabled the demonstration of position-sensitive detection applications. It demonstrates an exceptional position sensitivity of 14.9 mV/mm, an outstanding nonlinearity of 6.44%, and commendable trajectory tracking and optoelectronic demodulation capabilities. This study not only offers a promising route towards room-temperature MIR optoelectronic applications, but also demonstrates a great potential for application in optical sensing systems. [ABSTRACT FROM AUTHOR]

The regulation of carrier generation and transport by Schottky junctions enables effective optoelectronic conversion in optoelectronic devices. A simple and general strategy to spontaneously generate photocurrent is of great significance for self‐powered photodetectors but is still being pursued. Here, we propose that a photocurrent can be induced at zero bias by the transmittance contrast of MXene electrodes in MXene/semiconductor Schottky junctions. Two MXene electrodes with a large transmittance contrast (84%) between the thin and thick zones were deposited on the surface of a semiconductor wafer using a simple and robust solution route. Kelvin probe force microscopy tests indicated that the photocurrent at zero bias could be attributed to asymmetric carrier generation and transport between the two Schottky junctions under illumination. As a demonstration, the MXene/GaN ultraviolet (UV) photodetector exhibits excellent performance superior to its counterpart without transmittance contrast, including high responsivity (81 mA W–1), fast response speed (less than 31 and 29 ms) and ultrahigh on/off ratio (1.33 × 106), and good UV imaging capability. Furthermore, this strategy has proven to be universal for first‐ to third‐generation semiconductors such as Si and GaAs. These results provide a facile and cost‐effective route for high‐performance self‐powered photodetectors and demonstrate the versatile and promising applications of MXene electrodes in optoelectronics. [ABSTRACT FROM AUTHOR]

Solar‐blind photodetectors have attracted extensive attention due to their advantages such as ultra‐low background noise and all‐weather. In this study, the planar Ti/Ga2O3/Au Schottky avalanche photodetector (APD) is fabricated based on β‐Ga2O3 epitaxial film on the sapphire substrate grown by metal–organic chemical vapor deposition. The Schottky APD exhibits a high responsivity of 9780.23 A W−1, an ultrahigh photo‐to‐dark current ratio of 1.88 × 107, an external quantum efficiency of 4.77 × 106%, a specific detectivity of 9.48 × 1014 Jones, with an ultrahigh gain of 1 × 106 under 254 nm light illumination at 60 V reverse bias, indicating high application potential for solar‐blind imaging. The superior photoresponse performances ascribe to the effective carrier avalanche multiplication, which contributes to the high photocurrent, and the high quality Schottky junction depletion, which leads to the low dark current. [ABSTRACT FROM AUTHOR]

Semiconductor junctions are of great significance for the development of electronic and optoelectronic devices. Here, controllable switching is demonstrated from a Schottky junction to a p–n junction in a partially ionic liquid‐gated MoS2 device with two types of metal contacts. Excellent rectification behavior with a current on‐off ratio exceeding 106 is achieved in both Schottky and p–n junction modes. The formation of Schottky junction at the Pd electrode/MoS2 contact and p–n junction at the p‐MoS2/n‐MoS2 interface is revealed by spatially resolved photocurrent mappings. The switching between the two junctions under ionic gate modulation is correlated with the evolution of the energy band, further validated by the finite element simulation. The device exhibits excellent photodetection properties in the p–n junction mode, including an open circuit voltage up to 0.84 V, a responsivity of 0.24 A W−1, a specific detectivity of 1.7 × 1011 Jones, a response time of hundreds of microseconds and a linear dynamic range of up to 91 dB. The electric field control of such high‐performance Schottky and p–n junctions opens up fresh perspectives for studying the behavior of junction and the development of 2D electronic devices. [ABSTRACT FROM AUTHOR]

We present a straightforward approach to develop a high-detectivity silicon (Si) sub-bandgap near-infrared (NIR) photodetector (PD) based on textured Si/Au nanoparticle (NP) Schottky junctions coated with graphene film. This is a photovoltaic-type PD that operates at 0 V bias. The texturing of Si is to trap light for NIR absorption enhancement, and Schottky junctions facilitate sub-bandgap NIR absorption and internal photoemission. Both Au NPs and the texturing of Si were made in self-organized processes. Graphene offers additional pathways for hot electron transport and to increase photocurrent. Under 1319 nm illumination at room temperature, a responsivity of 3.9 mA/W and detectivity of 7.2 × 1010 cm × (Hz)1/2/W were obtained. Additionally, at −60 °C, the detectivity increased to 1.5 × 1011 cm × (Hz)1/2/W, with the dark current density reduced and responsivity unchanged. The result of this work demonstrates a facile method to create high-performance Si sub-bandgap NIR PDs for promising applications at ambient temperatures. [ABSTRACT FROM AUTHOR]

Sensitive and rapid detection of low‐power density ultraviolet (UV) light is of great significance for various applications such as space exploration, biological analysis, environmental sensors, communications, and imaging. However, the persistent photoconductivity (PPC) of photodetectors, which are based on ZnO, will cause a long decay time and make it difficult to capture weak light signals. In this work, the pyro‐phototronic effect of ZnO is integrated with the localized surface plasmon resonance (LSPR) of Ag nanoparticles (NPs) to enhance the performance of ZnO‐based photodetectors. The self‐powered photodetector is consisted of the ZnO nanowires (ZnO NWs) and Ag NPs, which can detect 325 nm UV light with a power density of 340 nW cm−2 quickly and sensitively. Compared with the photodetector without Ag NPs, the performance is significantly improved. Under the 325 nm UV light with the same power density, the best responsivity, and detectivity are 8.82 × 10−5 A W−1 and 4.9 × 1010 Jones, respectively. And the fast response time is remarkably reduced to 8.72 ms. These results help to understand the performance of LSPR enhanced photodetectors deeply and expand the methods for preparing high‐performance photodetectors. [ABSTRACT FROM AUTHOR]

The development of high-performance multispectral photodetector with narrowband and tunable spectral sensitivity is of importance but remains highly challenging to date. Here, we have reported on the fabrication of a Si Au/n-type Si/Au photodetector with tunable narrowband sensitivity not only in ultraviolet but also in near-infrared region, which is related to the controlled charge collection narrowing (CCN) mechanism. What is more, the negative response peak of the device can be readily tuned from 365 to 605 nm, and the positive response peak can be modulated from 938 to 970 nm when the bias varies from 0.1 to −0.1 V. In particular, the full-width at half-maximum is as small as 92 and 117 nm when the negative and positive response peaks approach the ultraviolet short wavelength end and near-infrared long wavelength end, respectively. The opposite polarity of the device responses in ultraviolet-visible and near-infrared regions renders the present Si photodetector potentially important in future multiple band optoelectronic systems. [ABSTRACT FROM AUTHOR]

In this work, a wavelength sensor that is capable of quantitatively distinguishing the wavelength in the range of ultraviolet (UV) to near-infrared (NIR) light (265–1050 nm) is presented. The wavelength sensor is fabricated by depositing two parallel Au electrodes on the two sides of a $200 ~\mu \text{m}$ Si wafer. It is found that the as-formed two photodetectors display completely different optical properties. And then, the relationship between the photocurrent ratio of two photodetectors and incident wavelength can be described as a numerical function, through which the wavelength from 265 to 1050 nm can be precisely calculated. The unique operation mechanism of the Si wavelength sensor is unveiled by technology computer-aided design (TCAD) simulation. Remarkably, the wavelength sensor easily distinguishes the light with a wavelength difference of 1 nm, which is much better than previously reported devices based on the vertically stacked structures and charge collection narrowing mechanism. [ABSTRACT FROM AUTHOR]

The ultra-long V 2 O 5 nanobelts were prepared by the improved PVD method. The performance of V 2 O 5 nanobelts photodetectors modified with Pt NPs was investigated from visible to near-infrared region, and the mechanism of enhancing the performance of V 2 O 5 nanobelts photodetectors modified by Pt NPs was revealed. [Display omitted] • Large-scale and ultra-long V 2 O 5 nanobelts have been prepared. • The property of the V 2 O 5 nanobelt photodetector is enhanced by modification with Pt NPs. • The mechanism of the formation of Schottky barrier by Pt modification is revealed. • The Pt NPs-modified V 2 O 5 nanobelt photodetector exhibits excellent performance. Schottky-contacted nanosensors have attracted extensive attention due to their high sensitivity and fast response time. In this article, we proved that the construction of Schottky contact by Pt nanoparticles (NPs) decoration can effectively improve the performance of V 2 O 5 nanobelts photodetectors. After modified by Pt NPs, the photocurrent of V 2 O 5 nanobelts is increased by more than two orders of magnitude, and the photoresponse speed is improved by at least three orders of magnitude. Detailed studies have shown that the performance enhancement is attributed to the formation of the Schottky contact at the electrode-semiconductor interface due to the decrease of surface gas adsorption and the increase of V 2 O 5 work function after Pt NPs modification. The strong built-in field in the Schottky barrier region will quickly separate photogenerated carriers, thereby reducing the electron-hole recombination rate, resulting in the fast response time and an increase in the free carrier density. Moreover, it is found that this enhancement effect can be regulated by controlling the pressure to modulating the Schottky barrier height at the interface. Overall, the Pt NPs-modified V 2 O 5 nanobelts photodetector exhibits a broad response spectrum (visible to near infrared), fast rise/fall response time (less than 6.12/6.15 ms), high responsivity (5.6 A/W), and high specific detectivity (6.9 × 108 Jones). This study demonstrates the feasibility of building a Schottky barrier to enhance the photodetection performance, which provides a general and effective strategy towards the construction and its practical application of supersensitive and fast-response nanosensors. [ABSTRACT FROM AUTHOR]

In particular, a remarkable photoresponse was observed in the graphene/SiO SB 2 sb /Ge regions at a drain bias of 3 V. These results suggest that a large photocurrent is generated in the graphene/SiO SB 2 sb /Ge regions owing to the self-gating effect of the graphene/SiO SB 2 sb /Ge capacitors by the drain bias. Keywords: germanium; graphene; photodetector; Schottky junction; split active junction EN germanium graphene photodetector Schottky junction split active junction 1041 1049 9 03/11/22 20220201 NES 220201 1 Introduction Various graphene/semiconductor Schottky junction photodetectors have been investigated to combine the benefits of graphene and semiconductors in terms of photonic responses [[1]], [[2]], [[3]], [[4]], [[5]], [[6]], [[7]], [[8]], [[9]], [[10]], [[11]], [[12]]. The reduced responsivity in devices with oxide widths greater than 20 m suggests that the photocarriers generated in the graphene/SiO SB 2 sb /Ge regions are farther away from the graphene/Ge junction, resulting in a weaker lateral electric field and consequently difficult to extract into the graphene/Ge junction before carrier recombination. High-performance near-infrared photodetectors based on gate-controlled graphene-germanium Schottky junction with split active junction. [Extracted from the article]

Owing to the intense carrier recombination and limited optical absorption, the as‐fabricated CsPbBr3 visible light photodetectors (PDs) are far from practical application. In this work, we have demonstrated performance‐improved metal‐semiconductor‐metal (MSM) structured CsPbBr3 visible light PDs realized by the decoration of sputtered Au nanoparticles (NPs). It showed that the Au NPs on the CsPbBr3 exhibited synergistic benefits including improving the photogenerated charge carriers' lifetime and enhancing the optical absorption of the CsPbBr3, both of which are fundamental factors for the performance‐improved PDs. Electrical characterizations showed that localized Schottky junctions formed at the Au NPs/CsPbBr3 interface. In addition, optical investigations showed that effective resonant coupling occurred between the localized surface plasmon resonance effects of Au NPs and excitons in the CsPbBr3. As a result, the on‐off switching of the Au‐decorated CsPbBr3 photodetector increased by 13 times compared with that of the pristine one. Meanwhile, the peak photo sensitivity of the CsPbBr3 photodetector was increased from 0.088 to 0.61 A W‐1 after the decoration of Au NPs. It is believed that the results shown in this work will provide pathways for fabricating high‐performance CsPbBr3 PDs and other similar devices in the future. [ABSTRACT FROM AUTHOR]

Emulating human vision for pattern classification is essential in intelligent machines, including pilotless vehicles and humanoid robots. Traditionally, analog visual information is captured by photosensors, which are sequentially classified using a physically separated algorithm‐based unit, such as a computer. Among such units, a self‐powered photodetector with a quick information sensing feature can be utilized for an unprecedented pattern classification; however, designing an ultrafast photodetector while maintaining a high sensitivity is critical. Herein, an alternative photovoltaic‐effect‐based, highly sensitive, self‐powered, broadband, ultrafast gradient junction nanoscale Schottky photodetector is introduced, that can sense input optical information without latency. Importantly, the proposed device can sense optical input within a ≈40 ns duration and demonstrate a 3‐dB bandwidth wider than 0.5 MHz, providing a throughput of 10 million bits per second. Photoconductive atomic force microscopy and Kelvin probe force microscopy independently revealed the photodynamic characteristic at a nanometer (≈35 nm) scale. Further, an array that can classify nontrivial patterns even with noisy inputs is developed. A unique solution to achieve an ultrafast photo response in self‐powered mode and classify the input patterns is provided. The proposed approach can be extended to several other artificial neural sensors, such as tactile, audio, and thermal sensors. [ABSTRACT FROM AUTHOR]

Recently reported ultraviolet (UV) detectors majorly focus on exploration of photodetection properties like photon absorption and electron‐hole pair generation to improve the photoresponsivity. However, UV sensors also have a potential advantage of monitoring the excessive UV exposure on skin. In this work, bismuth oxide/SnO2 quantum dots (QDs) vertical‐junction‐based self‐powered UV photodetector and optical UV filter are demonstrated. β‐Bi2O3 nanofibers are synthesized via electrospinning technique and SnO2 QDs are synthesized using a facile, single step hydrothermal process. Detailed morphological studies reveal the formation of 1D‐Bi2O3 and 0D‐SnO2. The fabricated self‐powered Bi2O2/SnO2‐based p–n heterojunction device exhibits a maximum responsivity of 62.5 µA W−1 and specific detectivity (D*) of 4.5 × 109 Jones attributing to the high absorption coefficient of β‐Bi2O2 nanofibers and SnO2 QDs in the UV region. Further, the 1D β‐Bi2O3 nanofibers and 0D SnO2 QDs are coated onto disposable cloth substrate to fabricate the UV optical filter which exhibits an exceptional ultraviolet protection factor of 159 and the photodetector device demonstrates high stability and reproducibility even after 1000 bending cycles. The strategy outlined here paves the way for development of bifunctional, cost‐effective design and construction of wearable UV sensors and protective devices for advanced nano‐electronic applications. [ABSTRACT FROM AUTHOR]

Titanium-doped Diamond-like carbon (Ti-DLC) has been previously used in photodetectors. However, these photodetectors suffer from large dark currents and long response times, limiting their practicality. In this study, we propose a Ti-DLC/Au/Si Schottky junction photodetector. We effectively suppressed the dark current by incorporating a thin layer of gold while enhancing the light current. The results showed the device shows the optimal performance when the gold is at 3 nm and the Ti-DLC thickness is 68 nm, the specific detectivity of the device reaches 1.8 × 1011 Jones and an optical-to-dark ratio exceeding 105 at zero bias voltage, and the response speed is in the range of tens of microseconds, significantly improving its performance. With its ability to suppress dark current, this Schottky junction photodetector holds excellent potential for various applications in the market. [Display omitted] [ABSTRACT FROM AUTHOR]

A self-powered ITO/ZnO/InP heterojunction photodetector has been demonstrated with a 10-nm ZnO interfacial layer deposited by atomic layer deposition as a hole-blocking layer. The presence of a valence band offset between InP and ZnO enhances the photocurrent. The valence band offset between InP and ZnO creates a sufficient barrier for hole movement. Low surface recombination under 520-nm laser irradiation produced maximum photoresponsivity of 44.2 mAW−1 with an illumination power of 1 µW at zero bias. The ZnO-passivated self-powered photodetector shows fast response and improved photo-detecting properties. Furthermore, the highly sensitive photodetectors are demonstrated to record the heart pulse wave by measuring relative changes in blood volume of the finger vessels. [ABSTRACT FROM AUTHOR]

The performance of a graphene/Ge Schottky junction near-infrared photodetector is significantly enhanced by inserting a thin Al2O3 interfacial layer between graphene and Ge. Dark current is reduced by two orders of magnitudes, and the specific detectivity is improved to 1.9 × 1010 cm ⋅ Hz1/2W−1. The responsivity is improved to 1.2 AW−1 with an interfacial layer from 0.5 AW−1 of the reference devices. The normalized photo-to-dark current ratio is improved to 4.3 × 107 W−1 at a wavelength of 1550 nm, which is 10–100 times higher than those of other Ge photodetectors. [ABSTRACT FROM AUTHOR]

Monolithic spectrometer is exceptionally attractive to enable compact, low‐cost spectroscopy for portable sensing and lab‐on‐a‐chip functionality. Unfortunately, simple down‐scaling of the microspectrometer size to the chip‐scale severely weakens light–matter interactions and degrades the sensor performance to unacceptable level. Unlike other state‐of‐the‐art miniature spectral splitting filters or photonic structures, bandgap‐graded nanowire strongly enhances the light‐matter interaction, which is a highly demanded yet unfulfilled feature for high‐precision on‐chip sensing. Here, on‐chip measurement of photoluminescence by a monolithic spectrometer made of a single composition‐graded CdSxSe1–x nanowire is reported. The nanowire is engineered to a waveguide‐mode‐operated, dispersive photodiode array. It works as a monolithic spectrometer chip with strong light–matter interaction and superior noise figure. On‐chip measurement of single‐point photoluminescence signals with 1013 Jones room‐temperature detectivity and 5 nm spectral resolution is illustrated. This demonstration of a compact, low‐cost, and high‐performance miniature spectrometer marks a major step towards on‐chip spectroscopy for fine resolution and sensitive detection. [ABSTRACT FROM AUTHOR]

Due to the advantages of narrow energy distribution of plasmonic hot-electrons in Ag and the high density of states in the TiO2 conduction band, an Ag/TiO2 composite is considered to be an ideal combination to construct a plasmonic hot-electron photodetector with high detectivity and a high response speed. In this work, we fabricate a porous Ag/TiO2-Schottky-diode based plasmonic hot-electron photodetector. This detector shows a high detectivity of 9.8 × 1010 cmHz1/2/W and a fast response speed, with a rise and fall time of 112 μs and 24 μs, respectively, under 450 nm light illumination at zero bias voltage. In addition, the height of the Ag/TiO2 Schottky barrier can be decreased by removing the chemisorbed oxygen from the surface of TiO2 with ultraviolet light illumination, and as a result, the responsivity of the Ag/TiO2 plasmonic hot-electron photodetector at 450 nm can increase from 3.4 mA/W to 7.4 mA/W. [ABSTRACT FROM AUTHOR]

Graphical abstract A self-powered Gr/Si heterojunction was successfully fabricated by using graphene film as active area. The device exhibits a responsivity approaching 39.5 mAW−1, together with a high-speed response speed up to 5.0 μs to communication wavelength of 1.55 μm. Highlights • A self-powered Gr/Si heterojunciton photodetector was fabricated by using graphene as the active area. • The Gr/Si heterojunciton photodetector shows an excellent rectification behavior and a sensitivity to 1.55 μm IR light. • High responsivity and high speed of the Gr/Si heterojunction were achieved. • The device performance are superior to most of previous graphene-based photodetectors. Abstract Graphene has shown great potentials for new-generation photodetectors in view of its outstanding optical and electrical properties, especially its ultra-broad range absorption. Most of graphene(Gr)/Si hybrid two-dimensional(2D)-three-dimensional(3D) photodetectors, which offer a perspective on future application in integrated optoelectronics, are still however enabled the excellent detection on visible light. Herein, we reported a self-powered Gr/Si Schottky heterojunciton with a high sensivity to communication light of 1.55 μm wavelenght by using graphene film as active area. The resultant photodetectors showed a high-speed response speed up to 5.0 μs, togther with a responsivity approaching 39.5 mAW−1, which are comparable with previous graphene-based photodetectors and superior to previous Gr/Si heterojunction. The high-performance of the schottky heterojunction can be ascribed to featuring a built-in field facilitating to separate photocarriers. Combined our results with the methodology of devcie fabrication, can be utilized as pathway for large-area integration of 1.55 μm communication light photodetectors. [ABSTRACT FROM AUTHOR]

Lead iodide (PbI2) single crystals have been extensively investigated due to their potential applications in nuclear radiation detectors at room temperature. In this letter, the properties of ultrathin PbI2 single crystals were obtained and investigated by X-ray diffraction, ultraviolet-visible diffuse reflection spectroscopy, and field emission scanning electron microscopy. The X-ray photodetector based on ultrathin PbI2 single crystal with a Schottky configuration of Au/PbI2/Mo was also fabricated through a facile method. Especially, the X-ray photodetector exhibits good stability and reproducibility. A large sensitivity of ${0}.{12} \times {10}^{{4}} \mu \text{C}$ /Gyair/cm2 was obtained for X-ray photodetector based on PbI2 single crystal at zero bias under a low radiation dose rate (0.19 mGy/h), which is sixty times higher than that of currently $\alpha $ -Se X-ray detectors at high bias. Moreover, we have further illustrated the working principles of the photodetector at zero, positive and negative bias with and without X-ray illumination. Our investigation substantiates the potential of the self-powered X-ray photodetector based on ultrathin PbI2 single crystal as a candidate device in optoelectronic applications. [ABSTRACT FROM AUTHOR]

The peculiar properties of the large absorption coefficient at near-infrared frequencies as well as their high mobility in germanium enable promising applications in photodetection. Schottky junctions based near-infrared photodetectors were fabricated by integrating monolayer graphene film with germanium membranes stacking on silicon oxide substrates (i.e., GeOI). The device exhibits a strong photovoltaic behavior, giving rise to high responsivity and detectivity of ∼62.1 mA W −1 and ∼2.1 × 10 11  cm Hz 1 / 2  W −1 , respectively. Time-response results indicate that the device could operate with the frequency up to 1 kHz. Our work may pave the way for exploiting graphene/GeOI Schottky junctions as the high-performance optoelectronic devices. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide (rGO)/silicon (Si) Schottky junction possesses promising attributes for various applications such as chemical sensor and photodetector. In this paper, a fabrication of simple back-to-back rGO/Si Schottky junction structure is presented. The device was fabricated via wet processes such as vacuum filtration, patterning by delamination, wet transfer and chemical reduction by ascorbic acid. From the current-voltage measurement, series resistance, barrier height and ideality factor were investigated at different temperature. Barrier height increases and ideality factor decreases with the increase of temperature indicating the inhomogeneity of the junction interface. By considering the Gaussian distribution of barrier height, the fabricated Schottky junction was shown to possess the mean barrier height of 1.24 eV with standard deviation value of 0.16 eV. The obtained mean barrier height was larger than the bandgap of Si, indicating the presence of thin insulation layer at the interface. [ABSTRACT FROM AUTHOR]

In this work, dual-wavelength UV photodetectors were successfully constructed by growing ZnO and MgZnO layers on SiO 2 substrates with ZnO/Au/MgZnO structure. The photodetectors exhibited high performance and the influence of different thickness of MgZnO layers was investigated. Moreover, simply by adjusting the applied voltage on the devices, the ratio of the two response peaks (caused by MgZnO and ZnO layers) changed therewith. The detecting properties may originate from the two layers having different increasing rates where the existence of Schottky junctions plays an important role. The photodetectors are meaningful for fabricating dual-wavelength optoelectronic devices for practical applications. [ABSTRACT FROM AUTHOR]

Abstract: The flexible fiber‐shaped photodetectors (PDs) suitable for wearable applications have recently attracted enormous research attention. However, the fiber‐shaped structures with the PN junction usually suffer from the poor interface between the all‐inorganic semiconductors and twisted linear electrodes. In this work, fiber‐shaped ZnO/graphene PDs based on a Schottky junction are constructed for the first time. The PDs exhibit excellent device performance because of the combination of the interface and strain engineering. In this novel structure, ZnO nanorod arrays are uniformly grown onto the Zn wire, and a graphene film is wrapped outside as the surface electrode. The built‐in electric field and the conformal contacts facilitate the separation and transport of photoinduced charge carriers. The photoresponsivity is as high as 1.92 A W−1. Moreover, the device performance can be further improved by applying external compressive strain due to the piezoelectric effect of ZnO. For instance, the responsivity of the PD under −0.33% compressive strain can increase by 12.5% and reach 2.16 A W−1. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the origin of the nonideal turn- ON characteristics of the graphene-silicon Schottky junction. Native oxide (SiO2) is proved to play a critical role in determining the behavior of a graphene-Si junction. Within the metal–oxide–semiconductor structure, the effective voltage drop across the junction degrades due to the capacitor network, which contributes to an increased ideality factor. Residual metal catalysts are detected, which act as recombination centers in the silicon and further degrade the ideality factor by enhancing the recombination current. The recombination current is found to be the dominant factor in making the junction nonideal. Forming gas annealing and the insertion of an interfacial dielectric restore the ideality of a graphene-Si junction by reducing the interface states and bulk recombination centers. [ABSTRACT FROM AUTHOR]

The development of new materials with facile synthesis and better semiconducting and photonic properties is crucial for the fabrication of durable thin film-based semiconductor devices. In this study, an organic semiconducting and photo-conducting metallogel has been obtained by deprotonation of the ligand SHAL using LiOH followed by treatment with Co(II) acetate in dimethylformamide (DMF) under ambient conditions. Various characterization techniques are used to analyze the mechanical, morphological, and optical properties. This analyses reveal the formation of a organic semiconducting Co(II)-metallogel with a nanofibrous architecture. Furthermore, a comprehensive analysis of this material in thin film form demonstrates its n-type organic semiconducting nature with a good rectification ratio in the Schottky diode configuration, among the best-known values of all these materials. The Co(II)-metallogel is analyzed based on its semiconducting properties as a self-powered (in absence of external bias voltage) photodetectors (PDs) in an ITO/Co(II)-metalogel/Au configuration, for the first time. The measured photocurrent demonstrates responsivity, R(λ), of 2.77 x 103, 0.27 x 103, and 0.025 × 103 mA/W, external quantum efficiency (EQE) of 73.4 x 104, 63.1 x 103, and 25 x 103, and detectivity (D) of 5.28 x 1012, 5.2 x 1011, 4.7 x 109 Jones, with on/off ratio of 16 080, 1580, and 150 at 0 V under the illumination of 470-nm (blue), 530-nm (green), and 630-nm (red) light sources, respectively. The high performance of the PDs is attributed to the UV–vis spectrum of the thin film, morphology, and metal-semiconductor energy band schematic outcomes. Overall, this study presents considerable potential for novel applications of Co(II)metallogels in technologically challenging electronic and optoelectronic devices. [Display omitted] • Development of organic semiconducting metallogel via facile technique. • The polymeric nature of the coordination using the various technique. • Investigation of semiconducting electronic and optoelectronic properties in thin film form. • PDs parameters R(λ) of 2.77 × 103 mA/W, EQE of 73.4 x 104, and D of 5.28 x 1012 Jones. [ABSTRACT FROM AUTHOR]

Abstract: Hybrid Perovskites have emerged as a class of highly versatile functional materials with applications in solar cells, photodetectors, transistors, and lasers. Recently, there have also been reports on perovskite‐based resistive switching (RS) memories, but there remain open questions regarding device stability and switching mechanism. Here, an RS memory based on a high‐quality capacitor structure made of an MAPbBr3 (CH3NH3PbBr3) perovskite layer sandwiched between Au and indium tin oxide (ITO) electrodes is reported. Such perovskite devices exhibit reliable RS with an ON/OFF ratio greater than 103, endurance over 103 cycles, and a retention time of 104 s. The analysis suggests that the RS operation hinges on the migration of charged ions, most likely MA vacancies, which reversibly modifies the perovskite bulk transport and the Schottky barrier at the MAPbBr3/ITO interface. Such perovskite memory devices can also be fabricated on flexible polyethylene terephthalate substrates with high bendability and reliability. Furthermore, it is found that reference devices made of another hybrid perovskite MAPbI3 consistently exhibit filament‐type switching behavior. This work elucidates the important role of processing‐dependent defects in the charge transport of hybrid perovskites and provides insights on the ion‐redistribution‐based RS in perovskite memory devices. [ABSTRACT FROM AUTHOR]

Transparent and flexible photodetector was realized by effective interfacial design methods. Silver nanowires (AgNWs) were networked onto a colorless polyimide (cPI) substrate to ensure the transparent conductive front electrode of Ni/ZnO/AgNWs/cPI photodetector. Under UV illumination, remarkable performances were obtained for quick responses (rise time = 0.987 ms and fall time = 2.49 ms) and ultrahigh responsivity (1.46 × 10 4 A/W). Due to the merit of AgNW-networks, an enhanced interfacial surface was established for the ZnO film, simultaneously providing efficiently short pathways for the collection of photo-generated carriers. The AgNWs-embedding Schottky photodetector gave an excellent noise equivalent power of 4.38 × 10 −15 W/Hz 1/2 , which is suitable for femtowatt-level photodetection. We demonstrate that the active adoption of metallic nanowires would provide high-degree of freedom for high-performing photoelectric devices with satisfying flexible and transparent features. [ABSTRACT FROM AUTHOR]

High-quality two-dimensional (2D) crystalline boron nitride nanosheets (BNNSs) were grown on silicon wafers by using pulsed plasma beam deposition techniques. Self-powered deep ultraviolet (DUV) photodetectors (PDs) based on BNNSs with Schottky contact structures are designed and fabricated. By connecting the fabricated DUV photodetector to an ammeter, the response strength, response time and recovery time to different DUV wavelengths at different intensities have been characterized using the output short circuit photocurrent without a power supply. Furthermore, effects of temperature and plasma treatment on the induced photocurrent response of detectors have also been investigated. The experimental data clearly indicate that plasma treatment would significantly improve both induced photocurrent and response time. The BNNS-based DUV photodetector is demonstrated to possess excellent performance at a temperature up to 400 °C, including high sensitivity, high signal-to-noise ratio, high spectral selectivity, high speed, and high stability, which is better than almost all reported semiconducting nanomaterial-based self-powered photodetectors. [ABSTRACT FROM AUTHOR]

In this study, we demonstrate a relatively independent UV photodetector which is composed of one layer of Au/Ag/Pt metal nanoparticles sandwiched between two layers of n-type TiO 2 semiconductor nanorods. Different from most reported Schottky junction based UV photodetectors, it can be driven only by two opposite Schottky junction in the sandwich structure, but no need for any external power supply except UV light when it works. Moreover, it displays high responsivity and fast response speed at the same time, giving a bright prospect for self-powered UV photodetectors. [ABSTRACT FROM AUTHOR]

One of the key limitations for the device performance of the silicon (Si) based photodetector arrays is the optical crosstalk effect encountered between photoactive elements as well. The scope of this work is to reduce optical crosstalk and thus increasing the device performances with graphene and Si integration. This paper presents the design, fabrication process, and performance evaluation of self-powered individual Graphene/Silicon on Insulator (GSOI) based Schottky barrier photodiode array (PDA) devices. A 4-element GSOI Schottky barrier PDA with separate graphene electrodes is fabricated to examine possible optical crosstalk encountered between each diode in the array structure. Here, monolayer graphene is utilized as hole collecting separate electrode on individually arrayed n-type Si on SOI substrate by photolithography technique. Each diode in the array exhibited a clear rectifying Schottky character. Photoresponse characterizations revealed that all diodes had excellent device performance even in self-powered mode in terms of an I light /I dark ratio up to 104, a responsivity of ∼0.12 A/W, a specific detectivity of around 1.6 × 1012 Jones, and a response speed of ∼1.32 μs at 660 nm wavelength. As revealed by optical crosstalk measurement, the device with pixel pitch of 1.5 mm had a total crosstalk of about 0.10% (−60 dB) per array. These results showed that the optical crosstalk between neighboring n-Si elements can be greatly minimized when graphene is used as separated electrode on arrayed Si on SOI substrate. Our study is expected give an insight into the performance characteristics of GSOI PDA devices which have great potential to be used in many technological applications such as multi-wavelength light measurement, level metering, high-speed photometry and position/motion detection. [Display omitted] • The devices exhibited strong rectification behavior with low leakage current and fast operation speed. • The devices had a spectral responsivity of ∼0.1 A/W with 104 on/off photocurrent ratio under self-powered operational mode. • Greatly reduced optical crosstalk in the G/n-Si linear photodiode array fabricated on silicon-on-insulator (SOI) substrate. • Compared to the device with common electrode, the optical crosstalk is decreased by 150% for the device with disconnected graphene electrode. [ABSTRACT FROM AUTHOR]

A self-powered, high-performance graphene/Silicon Carbide (G/4H-SiC) ultraviolet Schottky junction photodetector has been fabricated, and the effect of using monolayer and bilayer graphene on the device performance parameters was investigated. P-type graphene sheets were grown by the chemical vapor deposition (CVD) method, while 4H-SiC material consists of an epilayer structure of n-/n+ on bulk n-SiC. Two photodetector devices have been studied, one with monolayer graphene (MLG) and the other with bilayer graphene (BLG). The proposed photodetector structure reveals the highest spectral responsivity known of a G/4H-SiC UV photodetector so far. Electronic and optoelectronic characterizations were done under an ultraviolet wavelength range from 240 to 350 nm. The results show two spectral responsivity maxima (R max) at 285 nm and 300 nm wavelengths. Exhibiting two maxima in spectral responsivity and detectivity is caused by the constructive and destructive interference effects of multiple reflections at the SiC epilayer's interfaces. The photodetector devices exhibit high spectral responsivity (R ∼ 0.09 AW−1), maximum detectivity (D* ∼ 2.9 × 1012 Jones), and minimum noise equivalent power (NEP ∼ 0.17 pWHz-1/2) in both devices. Using bilayer graphene instead of monolayer showed no significant change in both the photogenerated current and the spectral responsivity due to the higher absorption coefficient of bilayer graphene, however, it exhibited a significant improvement in the response speed. The response speed was found to increase by 50 % when bilayer graphene was used as a hole collecting electrode in the G/4H-SiC junction. This is because bilayer graphene creates a narrower depletion layer and higher electric field, which promotes efficient charge separation and recombination. [Display omitted] • A self-powered, high-performance G/4H-SiC ultraviolet Schottky junction photodetector has been fabricated. • The impact of employing monolayer and bilayer CVD graphene on the device performance parameters was investigated. • The proposed photodetector structure reveals the highest spectral responsivity known for G/SiC UV photodetectors. • Two spectral responsivities were observed at 285 nm and 300 nm due to the constructive and destructive effects. • The photodetector with bilayer graphene provides an efficient charge separation, with a t r = 5.4 μs and t d = 3.2 μs. [ABSTRACT FROM AUTHOR]

In this letter, a novel photodetector based on graphene–PbSe van der Waals heterostructure for near-infrared detection is demonstrated. Generation and transportation of photocarriers are conducted in the PbSe photosensitive layer and graphene channel, respectively. The proposed structure is benefiting from the premium photoactivity of PbSe and high mobility of graphene with fast response time. Remarkable photoresponse was thus achieved. Photoresponse of the device can be controlled through the modulation on bias state of grapheme–PbSe Schottky heterojunction. The peak gain, responsivity, and detectivity are 7824, 6613 A/W, and $1.16\times 10^{12}$ Jones, respectively. With a response time at millisecond level, fast response speed is also achieved in this structure. [ABSTRACT FROM AUTHOR]

A self-powered metal–semiconductor Schottky diode with planar interdigital Au–Ti electrodes was fabricated and characterized for the detection of near-infrared light. The devices showed a significant increase in external quantum efficiency (EQE) and photoresponse at zero bias as electrode spacing reduces. A device with an electrode spacing of 5~\mu \textm exhibits EQE of 1% equivalent to responsivity of 6.45 mA/W at a wavelength of 800 nm and 0 V bias. Furthermore, the photocurrent to dark current ratio was 5\times 10^4 with a detectivity of 1.4\times 10^11 cm.Hz ^0.5 /W at 0 V bias. The recovery time constant was calculated from time-resolved photocurrent curve and found to be 0.19 s. The built-in electric field of the device was estimated to be on the order of 35 V/cm. [ABSTRACT FROM PUBLISHER]

Graphene/silicon heterostructures present a Schottky characteristic and have potential applications for solar cells and photodetectors. Here, we fabricated graphene/silicon heterostructures by using chemical vapor deposition derived graphene and n-type silicon, and studied the electronic and optoelectronic properties through varying their interface and silicon resistivity. The results exhibit that the properties of the fabricated configurations can be effectively modulated. The graphene/silicon heterostructures with a Si (111) interface and high resistivity show a better photovoltaic behavior and should be applied for high-performance photodetectors. With the combined atomic force microscopy and theoretical analysis, the possible origination is discussed. The work here should be helpful on exploring high-performance graphene/silicon photoelectronics. [ABSTRACT FROM AUTHOR]

In this article, a widely tunable graphene–liquid crystal photodetector is proposed and numerically investigated. The photodetector is composed of a single graphene layer on top of a silicon grating. Tunability is achieved by employing a liquid crystal layer which acts as a Fabry–Perot filter, yielding frequency selectivity. Detection mechanism is internal photoemission rising from Si/graphene Schottky​ junction. In the structure, Si grating determines the operation band, which can be tuned from less than 1. 5 μ m to more than 1. 7 μ m. For any specific Si grating, liquid crystal voltage controls the detection wavelength. It is shown that this tuning range can be as wide as 50 nm. Graphene fermi energy on the other hand, controls the absorption efficiency and detection linewidth. This independent separation of roles is a main advantage of the proposed structure, which makes the design process straightforward. Based on these functionalities, a tunable photodetector is designed at which the detection wavelength can be tuned from less than 1530 nm to more than 1570 nm covering the entire C communications band. For this tuning to take place, liquid crystal voltage is varied between 1.1 V and 4.2 V (RMS). Detection linewidth is as low as 2 nm making the photodetector ideal for optical communications, and the responsivity and quantum efficiency are 0.25 A/W and 20% respectively. Dependency of the photodetector characteristics on graphene fermi energy, liquid crystal voltage and Si grating parameters are fully discussed in the article. • Tunable narrow-band graphene–liquid crystal photodetector is presented. • Detection linewidth is approximately 2 nm, making the photodetector attractive for optical communications based on DWDM. • Without any structural modifications detection wavelength can be tuned from around 1520 nm to more than 1570 nm. • A silicon grating is used to make the structure highly resonant and achieve narrow linewidth. • Through changing the grating width and pitch, it is possible to select desired communications band. [ABSTRACT FROM AUTHOR]

The inefficient light absorption and gapless features of two-dimensional graphene (2D-graphene) severely impact quantum yield and electron-hole recombination, limiting its suitability in optoelectronics. Herein, a bottom 2D-graphene directly on the Ge substrate by chemical vapor deposition (CVD), a middle 3D-graphene is synthesized in-situ using 2D-graphene as the buffer layer via plasma-enhanced chemical vapor deposition (PECVD). A top 2D-graphene is transferred to 2D/3D-graphene/Ge by thermal release tape (TRT) technology to form a vertical 2D/3D/2D graphene sandwich cavity on the Ge substrate. The bottom 2D-graphene layer can not only perform as an interfacial layer for the in-situ preparation of 3D-graphene but also increase the electrical conductivity of the interface and advance the character of the Schottky junction formed between 3D-graphene/Ge, thereby improving the photon detection. The fabricated photodetector exhibits outstanding characteristics at a 1550 nm wavelength, with a high responsivity of 1.4 A/W and detectivity of 1.1 × 1014 Jones. This is due to the enhanced light absorption of the sandwich cavity and a high-quality interface layer (bottom 2D-graphene). The results reveal that this vertical 2D/3D/2D graphene sandwich architecture will facilitate the development of graphene-based NIR detection. [Display omitted] • The cavity consists of a 3D-graphene sandwiched between the top and bottom 2D-graphene. • The unique optical cavity enhances the interaction between 3D graphene and incident light. • The photodetector presents an excellent performance at [1–3,6] 1550 nm with high detectivity (1.1 × 1014 Jones) and responsivity (1.4 A/W). [ABSTRACT FROM AUTHOR]

ZnO nanowire (NW) UV photodetectors (PDs) have high sensitivity, while their long recovery time is an important limitation for practical applications. We demonstrated that the recovery time of nanostructured ZnO PDs can be significantly improved using the nanobelt (NB) network. The NB-network PDs are fabricated by only one step without tedious and costly lithography processes. As compared with a recovery time of 32.95 s in the single NB-based PD, a fast recovery time of 0.53 s observed in the NB-network PDs is achieved due to the existence of the NB–NB junction barriers. As the junction barriers accounting for the poor conductivity of NB networks hinder the electron transport, the dark current of the NB-network PDs is two orders of magnitude lower than that of the single NB-based PDs. The NB networks can be applicable to the building structures for nanostructured ZnO-based light-sensing applications with wafer-scale uniformity without compromising the unique photodetection properties exclusively provided by high surface-to-volume ratio and reduced dimensionality of an individual NW/NB. [ABSTRACT FROM PUBLISHER]

[Display omitted] • Ti 3 C 2 T x /GaAs Schottky junction photodetector is prepared by simply dripping Ti 3 C 2 T x MXene solution on GaAs substrate. • High responsivity of ~1.46 A/W, specific detectivity of ~1.23 × 1013 Jones are obtained when the device is operated in self-driven mode. • The photodetector exhibits a broadband response spectrum up to 980 nm due to plasmon-induced hot electrons in Ti 3 C 2 T x MXene film. As a novel family of 2D materials, MXenes are supposed to play a vital role in optoelectronic devices and systems due to their high conductivity, good optical properties, and favorable compatibility with water and organic solvents. However, the application of MXenes in highly sensitive photodetection is far scarcely investigated. Here, we demonstrate high-quality Ti 3 C 2 T x /GaAs Schottky junction by simply dripping Ti 3 C 2 T x MXene solution on a pre-patterned GaAs substrate. Owing to the wide absorption of MXene and the good quality junction, the self-driven Ti 3 C 2 T x /GaAs Schottky junction photodetector with an impressive performance is realized. The assembled photodetector exhibits a high sensitivity over a wide waveband with a good responsivity of ~1.46 A/W, a large specific detectivity of ~1.23 × 1013 Jones, and a high I light /I dark ratio of 5.6 × 105. Significantly, the photodetector is capable of sensing infrared light signal up to 980 nm which exceeds the absorption edge of GaAs (874 nm) due to the generation of hot electrons in Ti 3 C 2 T x MXene film. Given the superior device performance along with a simple and facile fabrication method, the Ti 3 C 2 T x /GaAs Schottky junction photodetector may find the great potential in high performance broadband, self-driven photodetection applications. [ABSTRACT FROM AUTHOR]

Si PN junction (p-Si/n-Si) photodetectors have been widely used in the near-infrared band. In this paper, the original p-Si is replaced by graphene to form a Gr/n-Si Schottky junction photodetector. Due to the excellent photoelectric properties of graphene, the incident light can irradiate the depletion region of the Schottky junction to generate more photo-generated carriers and has a higher barrier height, which corresponds to large electric field, and accelerates the photogenerated carriers to the electrodes, resulting in the effective collection of photogeneration of charges. The experimental results show that the Gr/n-Si Schottky junction photodetector has better performance. Under the illumination of 808 nm laser lamp, the I–V characteristic of the device was measured, the dark current of Gr/n-Si Schottky junction photodetector has reduced by two orders of magnitude, while the photocurrent was improved, the barrier height reaches 0.938 e V , and the quantum efficiency increases to 71%. Besides, the light responsivity and detectivity are significantly improved to about 0.456 A / W and 7.96 × 10 11 c m H z 1 / 2 W − 1 compared with the p-Si/n-Si photodetector. • The Graphene/n-Si Schottky junction photodetector was fabricated and compared with p-Si/n-Si photodetector. • The infrared light responsivity and detectivity of the Graphene/n-Si photodetector have been greatly improved. • The barrier heights of p-Si/n-Si interface and Graphene/n-Si interface were calculated to explain the performance improvement. [ABSTRACT FROM AUTHOR]

Schottky junction near-infrared photodetectors were constructed by combing monolayer graphene (MLG) film and bulk silicon. Notably, the device could operate at zero external voltage bias because of the strong photovoltaic behavior of the MLG/Si Schottky junction, giving rise to high responsivity and detectivity of 29 mAW^-1 and 3.9\times 10^11~cmHz^1/2W^-1, respectively, at room temperature. Time response measurement revealed a high response speed of 100 \mus, which allowed the device following a fast varied light with frequency up to 2100 Hz. In addition, the device showed great potential for low light detection with intensity <1~nWcm^-2 at 10 K. [ABSTRACT FROM AUTHOR]

• Surface treatment was conducted by soaking ZnO film into H 2 O 2 solution. • The contact between graphene and ZnO was transformed from ohmic to Schottky. • Graphene/H-ZnO PD exhibits a fast photovoltaic response to UV light at zero bias. • The fast response speed benefits from pyro-phototronic effect and built-in field. Compared to ZnO-based photoconductive photodetectors (PDs), photovoltaic PDs possess the advantages of easy fabrication, low dark current, high response speed and possible self-driven ability. In this paper, an ultraviolet (UV) photovoltaic photodetector based on graphene/ZnO heterostructure was fabricated and investigated. A simple surface treatment was conducted by soaking the as-grown ZnO film in H 2 O 2 solution at room temperature. After this processing, a transition from ohmic contact to Schottky contact was observed in graphene/ZnO interface, accompanied with a high-performance photovoltaic behavior for the graphene/H 2 O 2 -treated ZnO (denoted as G/H-ZnO) heterostructure. The self-powered Schottky photodetector of G/H-ZnO exhibits a responsivity of 50 μA/W and a short rise/decay time of 32 ms at zero bias. The fast response performance benefits from the rapid separation of photogenerated carriers, which can be attributed to the synergistic effect of pyroelectric potential and built-in electric field at graphene/ZnO interface. This study provides a facile approach for the development of ZnO-based self-powered photovoltaic devices. [ABSTRACT FROM AUTHOR]

As a remarkable potential material for optoelectronics, perovskite has been widely studied in photodetectors. Here, a channel structure on graphene is introduced to achieve efficient separation of carriers in perovskites by suppressing the leakage current. The fabricated horizontal graphene/perovskite/graphene (GPG) structure detector with a graphene–perovskite hybrid channel and a secondary perovskite channel shows a good performance with a responsivity of 22 mA W−1, on/off switch ratio of 2.6 × 103, and detectivity of 3.55 × 109 Jones at a bias voltage of 2 V and an effective area of 3 × 5 mm2. The channel prepared by a simple probe drawing process forms a horizontal Schottky structure that is effective in generating photocurrent. It is proposed that minimizing the thickness of the perovskite without reducing the absorption rate and maintaining one channel are effective ways to further improve the performance of the GPG detector. The photoresponse characteristics of the devices under illumination of different wavelengths are measured, showing wide spectral response range and linear optical power response. Finally, a flexible GPG detector on polyethylene terephthalate substrate is fabricated. It almost retains the same performance and shows good reliability and bendability. [ABSTRACT FROM AUTHOR]

A high‐responsivity near‐infrared photodetector is demonstrated using a transparent ZnO top gate‐modulated graphene/Ge Schottky junction. The responsivity of a graphene/Ge junction photodetector characterized with a scanning photocurrent microscopy system is improved to 0.75 A W−1. This result is 5 to 35 times higher than the previously reported graphene/Ge photodetectors that did not use gate modulation. The detectivity is also improved to 2.53 × 109 cm Hz1/2 W−1 at Vg = −10 V from 0.43 × 109 cm Hz1/2 W−1 at Vg = 0 V. The performance of this gate‐modulated graphene/Ge Schottky junction base infrared (IR) detector is comparable to a commercially available IR photodetector, but the fabrication process is much simpler and compatible with glass or flexible substrates. [ABSTRACT FROM AUTHOR]