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Oxygen partial pressure dependent UV photodetector performance of WO3 sputtered thin films
摘要： The influence of oxygen partial pressure (pO2) on the ultra-violet (UV) photodetector performance of WO3 thin films was studied. Here, the thickness of the WO3 thin films decreased from 225 nm to 150 nm with increasing the pO2 from 5% to 20%. The crystallinity of WO3 films decreased at higher pO2. The XPS analysis confirmed that the WO3 film deposited at 10% of pO2 had the more oxygen vacancies. The grain size of WO3 films decreased at higher pO2 grown conditions owing to the fragmentation of the oxide formation through the plasma. From current-voltage (I-V) measurements of WO3/Ti device, the ohmic-contact implies the formation of the metal-semiconductor junction with very less barrier height (?B) and it helps to the trapping of generated electrons for potential photodetector. Due to the higher number of incoming photons, the photocurrent was found to be increased as the power density increases. Finally, the WO3 film deposited at 10% of pO2 exhibits the higher photocurrent and quick rising time and hence this optimized thin film is suitable for UV-A photodetector.
关键词： Response time,WO3 film,Detectivity,Oxygen partial pressure,Photocurrent
更新于2025-09-19 17:13:59
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Enhancing Small-Molecule Organic Photodetector Performance for Reflectance-Mode Photoplethysmography Sensor Applications
摘要： Organic photodetector performance for enhancing the sensing abilities of an organic photoplethysmography sensor was investigated. Optimized organic photodetector with an anode interlayer and a cathode interlayer showed reverse dark current density of 22 nA cm-2 at ?2 V and the external quantum efficiency of 53.3% at 0 V. This organic photodetector was fabricated monolithically with an organic light emitting diode on a glass substrate to achieve a reflectance-mode photoplethysmography sensor, demonstrating the impact of organic photodetector device performance on the measured photoplethysmography signal for sensing applications. Furthermore, we estimated the optimal sensor design for circular geometry in terms of device area and distance between organic light emitting diode and organic photodetector to maximize the signal-noise ratio and lower the power consumption of organic photoplethysmography sensor devices. For most favorable photoplethysmography sensor design, signal strength of 130 mV with 600 μW power consumption was measured.
关键词： detectivity,Organic photodetector,OLED,Interlayer,dark current density,signal to noise ratio (SNR),PPG Sensor
更新于2025-09-19 17:13:59
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Industrial Applications of Nanomaterials || Nanomaterials-based UV photodetectors
摘要： Photodetectors are essential elements applied in video imaging, optical communications, biomedical imaging, security, night-vision, gas sensing, and motion detection, which possess the ability to transform light into electrical signals precisely. As the scale and diversity of application areas are growing, the need for innovative photodetection platform technologies with higher performance in terms of speed, efficiency or wavelength range, as well as material flexibility, transparency, and complementary metal-oxide-semiconductor (CMOS) integrability, is becoming more critical. In the past decades, extensive efforts have been devoted to explore the next generation of photodetector materials, such as In2Te3, ZnO, and GaN, with low noise, high photosensitivity, and good stability. However, many of these novel photodetector materials still suffer from limited photocurrent and photoresponse speed.
关键词： Nanomaterials,Schottky contacts,photoconductive gain,photodetection mechanism,photoresistors,linear dynamic range,responsivity,external quantum efficiency,photodiodes,specific detectivity,UV photodetectors
更新于2025-09-19 17:13:59
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Self-powered, all-solution processed, trilayer heterojunction perovskite-based photodetectors
摘要： Heterostructures composed of nano-/micro-junctions, combining the excellent photon harvesting properties of nano-system and ultrafast carrier transfer of micro-system, have shown promising role in high-performance photodetectors. Here, in this paper a highly-sensitive trilayer in which the CdS nanorods (NRs) layer is sandwiched between ZnO/CsPbBr3 interface to reduce self-powered perovskite-based photodetector ITO/ZnO(70nm)/CdS(150nm)/CsPbBr3(200nm)/Au, ratio of 106 with a responsivity of 86 mA/W and a specific detectivity of 6.2×1011 Jones was obtained at zero bias under 85 μW/cm2 405 nm illumination, and its rise/decay time at zero bias is to the strong built-in potential and the internal driving electric-field, an ultra-high On/Off current 0.3/0.25 s. Therefore, the enhanced device performance strongly suggest the great potential of such the interfacial charge carriers’ recombination and the charge transport resistance, is presented. Due a kind of trilayer heterojunction devices for high-performance perovskite photodetectors.
关键词： On/Off current ratio,CdS nanorods (NRs) layer,trilayer heterojunction,specific detectivity,gradient energy alignment,Self-powered photodetector,high-performance
更新于2025-09-19 17:13:59
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Fabrication of ?μ-Ga<sub>2</sub>O<sub>3</sub> solar-blind photodetector with symmetric interdigital Schottky contacts responding to low intensity light signal
摘要： Owing to the constraint of carrier transport, the dark current is relatively lower in Schottky contacted devices than that in Ohmic contacted devices, leading to a high specific detectivity in photodetectors. In this work, we prepared ε-Ga2O3 thin film by using metal-organic chemical vapor deposition, then constructed a three-pair interdigital ultraviolet solar-blind photodetector with Au electrodes as Schottky contacts. Seen from the results, this photodetector displays an outstanding wavelength selectivity with responsivity of 0.52 A W-1 responding to 250 nm wavelength light. In addition, it shows a photo-to-dark current ratio of 1.82 × 104/6.03 × 102 at 5 V under 40/5 μW cm-2 254 nm light illuminations, respectively, and a low dark current of 1.87 × 10-11 A. Correspondingly, the specific detectivity is 1.67 × 1012 Jones, and the photoresponsivity is 0.198 A W-1/52.54 mA W-1. Overall, ε-Ga2O3 prepared here is certified to be an excellent candidate material to perform high-performance solar-blind detection.
关键词： ε-Ga2O3,high detectivity,Schottky contact,solar-blind photodetector
更新于2025-09-19 17:13:59
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High‐Performance Flexible Broadband Photodetectors Based on 2D Hafnium Selenosulfide Nanosheets
摘要： 2D transition-metal dichalcogenides have attracted significant interest in recent years due to their multiple degrees of freedom, allowing for tuning their physical properties via band engineering and dimensionality adjustment. The study of ternary 2D hafnium selenosulfide HfSSe (HSS) high-quality single crystals grown with the chemical vapor transport (CVT) technique is reported. An as-grown HSS single crystal exhibits excellent phototransistor performance from the visible to the near-infrared with outstanding stability. A giant photoresponsivity (≈6.4 × 104 A W?1 at 488 nm) and high specific detectivity (≈1014 Jones) are exhibited by a device fabricated by exfoliating single-crystal HSS of nano-thickness on a rigid Si/SiO2 substrate. The application of HSS single crystal is extended to yield a sensible flexible photodetector of photoresponsivity up to ≈1.3 A W?1 at 980 nm. The photoresponsivity of CVT-grown HSS single crystal is significantly larger than those fabricated with other existing Hf-based chalcogenides. The results suggest that the layered multi-elemental 2D chalcogenide single crystals hold great promise for future wearable electronics and integrated optoelectronic circuits.
关键词： crystal growth,photoresponsivity,transition metal dichalcogenides,flexible optoelectronics,specific detectivity
更新于2025-09-19 17:13:59
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Wafer-size growth of 2D layered SnSe films for UV-Visible-NIR Photodetector Arrays with High Responsitivity
摘要： Due to its excellent electrical and optical property, tin selenide (SnSe), a typical candidate of two-dimentional (2D) semiconductors, has attracted great attention in the field of novel optoelectronics. However, the large-area growth of high-quality SnSe films still remain a great challenge which limit its practical applications. Here, wafer-size SnSe ultrathin films with high uniformity and crystallization are deposited via a scalable magnetron sputtering method. The results show that the SnSe photodetector is highly sensitive to a broad wavelength in the UV-Visible-NIR range, especially showing an extremely high responsivity of 277.3 A W -1 with the corresponding external quantum efficiency of 8.5×104% and detectivity of 7.6×1011 Jones. These figures-of-merits are among the best performance for the sputter-fabricated 2D photodetector devices. The photodetecting mechanisms based on a photogating effect induced by the trapping effect of the localized defects are discussed in details. The results indicate that the few-layered SnSe films from the sputtering growth would have great potential in designing high-performance photodetector arrays.
关键词： tin selenide,detectivity,responsivity,optoelectronics,SnSe,UV-Visible-NIR,2D semiconductors,external quantum efficiency,photodetector,magnetron sputtering
更新于2025-09-19 17:13:59
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A remarkable effect of Pr doping on key optoelectrical properties of CdS thin films prepared using spray pyrolysis technique for high-performance photodetector applications
摘要： High-quality thin film-based photodetectors containing praseodymium doped cadmium sulfide (Pr:CdS) were fabricated through spray pyrolysis and studied for various opto-electrical applications. Field emission electron microscopy (FE-SEM) revealed that the prepared films were highly compacted with an extremely fine nanostructure without any pinhole or crack. X-ray diffraction and FT-Raman spectroscopy studies confirmed the single hexagonal phase of all the films. The crystallite size was found to lie between 19 and 32 nm. Optical spectroscopy revealed that the fabricated films have low absorbance and high transmittance (in range of 70–80%). The energy gap was found to lie in the range of 2.40–2.44 eV. The PL spectra contained an intense green emission band at ~531 ± 5 nm (2.33 eV), and its intensity was enhanced by increasing the Pr doping content in CdS. The dark and photo currents of CdS increased by approximately 950 and 42 times, respectively with the addition of 5.0 wt.% Pr. The responsivity (R) and specific detectivity (D*) were remarkably enhanced to 2.71 AW-1 and 6.9×1011 Jones, respectively, for the 5.0 wt.% Pr:CdS film. The external quantum efficiency (EQE) of 5 wt.% Pr:CdS films was 43 times that of pure CdS films, and the on/off ratio was 3.95 × 102 for 5.0 wt.% Pr:CdS film. Its high R, D*, and EQE values, and photo-switching behavior make Pr:CdS a good contender for high quality photodetector applications.
关键词： responsivity,external quantum efficiency,detectivity,CdS and Pr: CdS films,opto-electrical properties
更新于2025-09-19 17:13:59
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Giant detectivity of ZnO-based self-powered UV photodetector by inserting an engineered back gold layer using RF sputtering
摘要： The realization of high-responsivity, self-powered and low-cost ultraviolet (UV) photodetector (PD) based on eco-friendly and earth-abundant compounds, remains far from satisfactory for future optoelectronic applications. In this paper, we demonstrated a new high-performance UV-PD based on planar ZnO thin-film, efficiently operating without any power supply. The proposed device was elaborated by evaporating an engineered back metallic layer onto the glass substrate and then depositing ZnO thin layer through RF sputtering technique. The sensor structural and optical properties were systematically analyzed by the techniques of X-ray diffraction (XRD) and UV–Vis absorbance spectrometry. The resulted ZnO UV-PD showcased a clear and distinctive photovoltaic behavior. Interestingly, it also demonstrated a high responsivity of 0.38A/W and a giant detectivity exceeding 1014 Jones at zero bias, which is much higher than other reported self-powered UV-PD despite the use of an All-ZnO structure. The device photodetecting mechanism in self-driven mode was discussed using the energy band diagram, where the key role of the engineered back metallic layer in modulating the electric field distribution within the ZnO active region to effectively achieve an asymmetric behavior is emphasized. Therefore, the presented work offers a novel pathway to design high-responsivity self-powered UV-PDs based on a simple All-ZnO structure.
关键词： detectivity,ZnO,Self-powered,low cost,UV photodetectors,RF sputtering
更新于2025-09-16 10:30:52
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[IEEE 2018 IEEE 8th International Conference Nanomaterials: Application & Properties (NAP) - Zatoka, Ukraine (2018.9.9-2018.9.14)] 2018 IEEE 8th International Conference Nanomaterials: Application & Properties (NAP) - Semi-transparent UV Photodetectors Based on the Nanostructured n-ZnO/p-CuI and n-ZnO/p-NiO Diode Heterojunctions Prepared by Low Temperature Solution Growth
摘要： In this work we investigate wide band-gap bipolar diode nanostructured heterojunctions prepared by low temperature solution growth. The crystal structure and optical properties of the pulsed electrodeposited zinc oxide nanorod arrays and nickel oxide and copper iodide films grown via Successive Ionic Layer Adsorption and Reaction (SILAR) technique, and also diode parameters and photoelectric characteristics of the heterojunctions show that they are promising for a fabrication of low cost and portable semi-transparent photodetectors of soft ultraviolet light.
关键词： ultraviolet photodetector,copper iodide,nickel oxide,nanocrystal structure,specific detectivity,zinc oxide
更新于2025-09-16 10:30:52