Self-powered Detectors Research Articles

Ultraviolet-Visible-Near-Infrared Broadband Photodetector Enabled by Cs2AgBiBr6: Sn/Conjugated Polymer Heterojunction.

Broadband photodetectors covering ultraviolet (UV) to near-infrared (NIR) wavelengths play an essential role in communications, imaging, and biosensing. Developing a single photodetector with a broadband optical response operating at room temperature can significantly reduce the complexity and cost of receiver systems for multispectral applications. In this work, utilizing the porous structure characteristics of Cs2AgBiBr6:Sn thin films, a self-powered detector with broad spectral response (UV-vis-NIR) was achieved by constructing an effective Cs2AgBiBr6:Sn/PDPP3T heterojunction. This photodetector possesses a broad response spectrum from 350 to 950 nm with an average detection rate exceeding 1011 Jones and maintains excellent photoelectric performance over two months. Sn2+ doping effectively reduces the bandgap of Cs2AgBiBr6, enhancing its near-infrared absorption and optimizing energy level alignment with conjugated polymer (diketopyrrolopyrrole-terthiophene, PDPP3T). More importantly, the porous structure derived from Sn doping significantly improves carrier extraction and transport under a near-infrared light response at the heterojunction interface. Utilizing its broad spectral response characteristics in the UV-vis-NIR range, a novel information transfer and encryption system employing full optical modulation has been realized within a single perovskite photodetector. This work provides a new approach to fabricating lead-free double perovskite broadband photodetectors with potential applications in photonic devices.

Radiation hardness characteristics of self-powered detector based on SiC/Si heterojunction diode

Radiation hardness characteristics of self-powered detector based on SiC/Si heterojunction diode

Solution-Grown MAPbBr3 Single Crystals for Self-Powered Detection of X-rays with High Energies above One Megaelectron Volt.

Perovskite single crystals are actively studied as X-ray detection materials with enhanced sensitivity. Moreover, the feasibility of using perovskites for self-powered devices such as photodetectors, UV detectors, and X-ray detectors can significantly expand their application range. In this work, the charge carrier transport and photocurrent properties of MAPbBr3 single crystals (MSCs) are improved by the mechanochemical surface treatment using glycerin combined with an additional electrode design that forms an ohmic contact. The sensitivity of MSC-based detectors and pulse shape generated by X-rays are enhanced at various bias voltages. The synthesized MSC detectors generate direction-dependent photocurrents, which indicate the presence of a polarization-induced internal electric field. In addition, photocurrent signals are produced by X-rays with energies greater than 1 MeV under a zero-bias voltage. This work demonstrates a high application potential of perovskites as self-powered detectors for X-rays with energies exceeding 1 MeV.

Self-Powered Solar-Blind UV Detectors Based on O-Terminated Vertical Diamond Schottky Diode with Low Dark Current, High Detectivity, and High Signal-to-Noise Ratio

Self-powered solar-blind UV detectors were fabricated using high-quality Ru/diamond Schottky diodes. Photocurrents of 1 nA and 1.3 nA were obtained for detector Semi and Mesh under the condition of zero bias and 220 nm UV light irradiation, while the dark currents of these two detectors were 0.53 pA and 0.007 pA at 0 V, respectively. Photosensitive areas of detector Semi and Mesh were 1 mm2 and 0.74 mm2, respectively. Rectification ratios as high as 1.5 × 107 and 5.7 × 108 at ±5 V for Semi and Mesh were obtained, showing good rectifying characteristics for the vertical Schottky diodes. Responsivities at 0 V of Semi and Mesh were 10.3 mA/W and 16.2 mA/W, respectively. High detectivities of 3.8 × 1012 Jones and 5.2 × 1013 Jones for detector Semi and Mesh indicate excellent self-powered detection performance. To make a comprehensive comparison of the performance of diamond solar-blind UV detectors, a log(Iph) versus log(Idark) graph was proposed, and the detector in this work showed an ultrahigh SNR of 2 × 105. A high linear dynamic range of 105.9 dB was achieved for the self-powered detector Mesh.

Highly efficient UV detection in a metal–semiconductor–metal detector with epigraphene

We show that epitaxial graphene on silicon carbide (epigraphene) grown at high temperatures (T >1850 °C) readily acts as material for implementing solar-blind ultraviolet (UV) detectors with outstanding performance. We present centimeter-sized epigraphene metal–semiconductor–metal (MSM) detectors with a peak external quantum efficiency of η ∼ 85% for wavelengths λ = 250–280 nm, corresponding to nearly 100% internal quantum efficiency when accounting for reflection losses. Zero bias operation is possible in asymmetric devices, with the responsivity to UV remaining as high as R = 134 mA/W, making this a self-powered detector. The low dark currents Io ∼ 50 fA translate into an estimated record high specific detectivity D = 3.5 × 1015 Jones. The performance that we demonstrate, together with material reproducibility, renders epigraphene technologically attractive to implement high-performance planar MSM devices with a low processing effort, including multi-pixel UV sensor arrays, suitable for a number of practical applications.

Design of effective self-powered SnS2/halide perovskite photo-detection system based on triboelectric nanogenerator by regarding circuit impedance

Self-powered detectors based on triboelectric nanogenerators (TENG) have been considered because of their capability to convert ambient mechanical energy to electrical out-put signal, instead of conventional usage of electrochemical batteries as power sources. In this regard, the self-powered photodetectors have been designed through totally two lay out called passive and active circuit. in former model, impedance matching between the TENG and the resistance of the circuit’s elements is crucial, which is not investigated systematically till now. In this paper, a cost effective novel planar photodetector (PD) based on heterojunction of SnS2 sheets and Cs0.05(FA0.83 MA0.17)0.95Pb(I0.83Br0.17)3 three cationic lead iodide based perovskite (PVK) layer fabricated which powered by graphene oxide (GO) paper and Kapton based contact-separated TENG (CS-TENG). To achieve the high performance of this device, the proper range of the load resistances in the circuit regards to TENG’s characterization has been studied. In the next steps, the integrated self-powered photo-detection system was designed by applying Kapton/FTO and hand/FTO TENG, separately, in the proposed impedance matching circuit. The calculated D* of integrated self-powered SnS2/PVK supplied by tapping the Kapton and hand on FTO is 2.83 × 1010 and 1.10 × 1013 Jones under the 10 mW/cm2 of white light intensity, the investigations determine that for designing significate performance of self-powered PD supplied by TENG, the existence of the load resistance with the well match amount to the utilized TENG is crucial. Our results which can be generalized to other types of passive self-powered sensors, are substantial to both academia and industry concepts.

α-Fe2O3 Nanoparticles Aided-Dual Conversion for Self-Powered Bio-Based Photodetector.

Eco-friendly energy harvesting from the surrounding environment has been triggered extensive researching enthusiasm due to the threat of global energy crisis and environmental pollutions. By the conversion of mechanical energy that is omnipresent in our environment into electrical energy, triboelectric nanogenerator (TENG) can potentially power up small electronic devices, serves as a self-powered detectors and predominantly, it can minimize the energy crisis by credibly saving the traditional non-renewable energy. In this study, we present a novel bio-based TENG comprising PDMS/α-Fe2O3 nanocomposite film and a processed human hair-based film, that harvests the vibrating energy and solar energy simultaneously by the integration of triboelectric technology and photoelectric conversion techniques. Upon illumination, the output voltage and current signals rapidly increased by 1.4 times approximately, compared to the dark state. Experimental results reveal that the photo-induced enhancement appears due to the effective charge separation depending on the photosensitivity of the hematite nanoparticles (α-Fe2O3 nanoparticles) over the near ultraviolet (UV), visible and near infrared (IR) regions. Our work provides a new approach towards the self-powered photo-detection, while developing a propitious green energy resource for the circular bio-economy.

Self-powered asymmetric metal-semiconductor-metal AlN deep ultraviolet detector.

Self-powered ultraviolet detectors may find application in aviation and military fields. Here we demonstrate a self-powered asymmetric metal-semiconductor-metal (MSM) deep ultraviolet (DUV) detector with an Ni/Al electrode contact to AlN, and a photoelectric response current increase from dark current (Id) 2.6 × 10-12 A to 1.0 × 10-10 A after UV illumination (Ip) at 0 V bias. To further improve device performance, trenches are etched in AlN, and the Ni/Al electrodes are deposited in trenches to form a three-dimensional MSM (3D-MSM) structure. The improved performance is attributed to the stronger electric field from the asymmetric electrode and a shorter carrier migration path from the 3D-MSM device configuration. Our work will promote the development and application of DUV self-powered devices.

Ultra-high performance self-powered radiation detector based on Si heterojunction

Self-powered detectors are highly significative in the applications of radiation detection in some harsh or limited space environment compared with the conventional detectors. Hence, we present a self-powered radiation detector with heterojunction structure formed by an ultra-thin oxide layer combined with heavily doped polycrystalline silicon layer. One outstanding advantage of the heterojunction structure is selective collection of carriers for lowering the recombination of signal carriers. The electrical characteristics were investigated from current–voltage and capacitance–voltage measurements, and the capability of radiation detection were performed by X-ray and α-sources. In the self-powered mode, detector showed low dark current of 1.5 nA/cm2, good linear response to X-ray dose rate, perfect charge collection efficiency of more than 87%, and superior energy resolution within 2.2% for 239Pu α-source spectral measurement. Besides, performance of the detector at the reverse bias from 0 V to 50 V were tested to further verify the detector’s reliability.

A UV-enhanced, self-powered detector with graphene p–n junction grown in situ on SiC(0001) with periodic boron ion modulation

Graphene p–n junctions hold great potential in the fields of electronic and optoelectronic devices. Here, we develop a scheme of the in situ growth of an epitaxial graphene (EG) lateral p–n junction on a semi-insulating SiC (0001) substrate with periodic boron ion implantation, and utilizing the advantages of EG, SiC, and p–n junctions in a two-terminal device at the same time, a high-performance UV-enhanced self-powered photodetector is prepared based on an EG p–n junction with a maximum Fermi level difference of about 210 mV. Moreover, when a 325-nm laser locally irradiates the p-terminal of the device, its responsivity is about six times higher than when the laser locally irradiates the n-terminal. This indicates that EG on SiC with a p-type modulated subsurface is conducive to designing efficient UV photodetectors in which SiC serves as the gain medium. All of these characteristics facilitate the growth of EG p–n junctions on a wafer scale and the fabrication of EG p–n junctions for optoelectronic and electronic devices using standard semiconductor synthesis procedures.

Monte Carlo analyses of the fusion neutron and gamma signals from the chromium self-powered detector.

To test the applicability of self-powered detectors (SPDs) for radiation monitoring in fusion reactor blankets, several irradiation tests have been undertaken with the ad hoc designed Cr-SPD, which presents the novelty of using chromium as the emitter material. This detector was exposed to an intense 60Co gamma-ray source, and to the 14MeV neutrons produced by the D-T fusion reaction. Detailed analyses of the measured signals have been done here using a Monte Carlo modeling technique. We describe the simulations of the fusion neutron and gamma tests of the Cr-SPD, and compare their results with the experimental ones. Keeping in view the difficulty in computational reproduction of the sophisticated nuclear-electrical phenomena behind low-level SPD signals, our model is found to perform well, giving correct electrical polarities and orders of magnitude of the signals, as well as valuable insights into their different components. Our experience has highlighted the deficits and the needed improvements for the traditional SPD simulation techniques for prompt signal analyses.

Acquiring and Modeling of Si Solar-Cell Transient Response to Pulsed X-Ray

We report on the acquisition and modeling of the transient response of a commercial silicon (Si) solar cell using a benchtop pulsed X-ray source. The solar-cell transient output to the X-ray pulses was acquired under the dark and steady-state light illumination to mimic the practical operation of a solar cell under different light illumination levels. A solar-cell circuit model was created to develop a fundamental understanding of the transient current/voltage response of solar cell at read-out circuit level. The model was validated by a good agreement between the simulation and experimental results. It was found that the solar-cell resistance ( R) and capacitance ( C) depend on the light illumination, and the resulting variation in RC time constant significantly affects the solar-cell transient response. Thus, the solar cell produced different transient signals under different illumination intensities in response to the same X-ray pulse. The experimental data acquired in this work proves the feasibility of using solar panels for prompt detection of nuclear detonations, which also builds a practical mode of X-ray detection using a low-cost self-powered detector.

Ferroelectricity-Driven Self-Powered Ultraviolet Photodetection with Strong Polarization Sensitivity in a Two-Dimensional Halide Hybrid Perovskite.

Polarization-sensitive ultraviolet (UV) photodetection is highly indispensable in military and civilian applications and has been demonstrated with various wide-band photodetectors. However, it still remains elusive to achieve the self-powered devices, which can be operated in the absence of external bias. Herein, for the first time, ferroelectricity-driven self-powered photodetection towards polarized UV light was successfully demonstrated in a 2D wide-band gap hybrid ferroelectric (BPA)2 PbBr4 (BPA=3-bromopropylammonium) (1). We found that the prominent spontaneous polarization in 1 results in a bulk photovoltaic effect (BPVE) of 0.85 V, that independently drives photoexcited carriers separation and transport and thus supports self-powered ability. This self-powered detector shows strong polarization sensitivity to linearly polarized UV illumination with a polarization ratio up to 6.8, which is superior to that of previously reported UV-polarized photodetectors (ZnO, GaN, and GeS2 ).

Self-Powered Flexible All-Perovskite X-Ray Detectors with High Sensitivity and Fast Response

Perovskite materials have demonstrated superior performance in many aspects of optoelectronic applications including X-ray scintillation, photovoltaic, photodetection and etc. In this work, we demonstrate that a self-powered flexible all-perovskite X-ray detector with high sensitivity and fast response can be realized by integrating CsPbBr 3 perovskite nanocrystals (PNCs) X-ray scintillator with CH3NH3PbI3 perovskite photodetector. The PNCs scintillator exhibits ultra-fast light decay of 2.81 ns, while the perovskite photodetector gives fast response time of ~0.3 μs and high specific detectivity of ~ 2.4×1012 Jones. The synergistic effect of these two components ultimately leads to self-powered flexible all-perovskite X-ray detector that delivers high sensitivity of 600-1270 μCmGyair-1cm-3 under X-ray irradiation and fast radiation-to-current response time.

Material-to-device performance correlation for AlGaN-based solar-blind p–i–n photodiodes

We report on crystalline quality-to-device performance correlation for self-powered Al0.40Ga0.60N, p–i–n ultraviolet (UV) photodetectors on c-plane sapphire. The active p–i–n detector stack was grown over an AlN buffer. Careful optimization of the nucleation density on growth surface helped achieve a two-orders and one-order of magnitude reduction in the screw and edge dislocation density in the buffer layer, respectively. This resulted in a nine-orders of magnitude reduction in the reverse leakage current from 4.3 mA to 4.2 pA (at 10 V). Correspondingly, a thirteen-fold enhancement in the zero-bias external quantum efficiency (EQE) from 3.4% to 45.5%, when measured under 289 nm front-illumination was also observed. The detector epi-stack grown over the optimal AlN buffer layers led to the realization of high-performance p–i–n detectors with a dark current density below 4 nA cm−2 at 10 V and a zero-bias EQE of 74.7% under back-illumination. This is one of the highest zero-bias EQE reported for solar-blind detectors realized on template-free and mask-free III-nitrides grown using metal organic chemical vapor deposition on any substrate. The deep-UV-to-visible rejection ratio exceeded 106 while the deep-UV-to-near UV rejection exceeded 103. The thermal-noise limited detectivity was estimated to be 4 × 1014 cm Hz1/2 W−1. Hopping conduction along screw dislocation-mediated localized trap states was found to be the dominant carrier transport mechanism in the samples exhibiting high reverse leakage. For these samples, the responsivity (photocurrent) exhibited an exponential variation with reverse bias and a nonlinear variation with input optical power. This is explained using a hole-trapping associated gain mechanism and its impact on the transient characteristics of the detectors is investigated. A 6 × 1 linear array of the highest EQE detectors was realized and detector performance parameters were found to be comparable before and after wire bonding. This study is expected to enhance the understanding of III-nitrides-based vertical, self-powered detectors and benefit the development of high-performance, focal plane arrays using less complicated growth techniques.

MONACO v2: Multipurpose and Integrated Data Acquisition System for On-line Neutron and Gamma Measurements

The CEA MONACO v2 a multichannel acquisition system dedicated to neutron and gamma measurements. It is unique as it integrates all the following features in one module: automatic generation of saturation curves, automatic generation of pulse discrimination curves, detector pulse characterization using the embedded oscilloscope module, pulse mode acquisitions in count rate or pulse height analysis, fluctuation mode and current mode acquisitions. Sensors are plugged to a single connector and the implemented operating modes run constantly in parallel. Firsly designed for on line local neutron and gamma measurements with gaseous detectors in reactor experiments, the MONACO v2 system will also be available for self-powered detectors thanks to its wide current mode working range. After two years of development, CEA teams tested two MONACO v2 prototypes in the Slovenian TRIGA Mark II research reactor in 2018, using CEA miniature ion chambers and SPNDs. The system is now ready for industrialization to be available on the nuclear instrumentation market.

РАСЧЁТ ПО ПРОГРАММАМ MCU-PD И ТВС-М ПОКАЗАНИЙ ДЕТЕКТОРОВ ПРЯМОЙ ЗАРЯДКИ

For successful licensing and safe passage of pilot operation of a new type of fuel in the core of an operating VVER-1000 reactor, it is necessary to carry out a preliminary validation of design codes that are routinely used for developing fuel cycles, core safety analysis and calculating maintenance of power unit operation. Validation matrix of the design codes includes problems of calculating transition functions of self-powered neutron detector (SPND). SPNDs are the part of incore monitoring system, which allows to determine power density in the core of an operating power unit. Transition functions from the self-powered detector current to the power density are calculated by means of TVS-M spectrum code. For each type of FA and each instance of self-powered detectors, transition functions are calculated in advance. Transition functions are never corrected during operation, therefore, strict requirements are imposed to the accuracy of their calculation. The main objective of the work is a comparative analysis of the TVS-M spectrum code and the MCU-PD Monte Carlo code as applied to the calculation of transition functions of self-powered neutron detectors for VVER fuel assemblies. During the work, we created calculation models of several types of fuel assemblies, differ in type of fuel, presence of fuel rods with Gd, and placement of SPND. We performed several series of calculations of the created FAs at different burnup steps. The calculations were carried out in states with different coolant parameters, fuel temperatures and presence of control rods. As the target functionals, we considered SPND current, SPND transition function and power density factor of six fuel rods surrounding SPND. We determined maximum relative deviations of TVS-M from MCU-PD in the target functionals calculation. We confirmed acceptable accuracy of calculations of the target functionals by means of TVS-M code for wide range of reactor parameters. We also estimated the influence of homogenization of the SPND structure on the accuracy of transition function calculation.

Nanowires promise self-powered UV detectors

Nanowires promise self-powered UV detectors

High-Bandwidth InGaN Self-Powered Detector Arrays toward MIMO Visible Light Communication Based on Micro-LED Arrays

This work reports the use of the chip-based GaN-based micro-LED (μLED) arrays for multifunctional applications as microdisplay, data transmitters, photodetectors, and solar cells. The functions of ...

A Self-powered Always-on Vision-based Wake-up Detector for Wearable Gesture User Interfaces

A Self-powered Always-on Vision-based Wake-up Detector for Wearable Gesture User Interfaces