UV-light-assisted gas sensor based on PdSe/InSe heterojunction for ppb-level NO sensing at room temperature.

The fabrication of van der Waals (vdWs) heterostructures mainly extends to two-dimensional (2D) materials. Nevertheless, the current processes for obtaining high-quality 2D films are mainly exfoliated from their bulk counterparts or by high-temperature chemical vapor deposition (CVD), which limits industrial production and is often accompanied by defects. Herein, we first fabricated the type-II p-PdSe/n-InSe vdWs heterostructure using the ultra-high vacuum laser molecular beam epitaxy (LMBE) technique combined with the vertical 2D stacking strategy, which is reproducible and suitable for high-volume manufacturing.

Sensitive Silicon Nanowire Ultraviolet B Photodetector Induced by Leakage Mode Resonances.

Ultraviolet photodetectors (UVPDs) have played an important role both in civil and military applications. While various studies have shown that traditional UVPDs based on wide-band-gap semiconductors (WBSs) have excellent device performances, it is, however, undeniable that the practical application of WBS-based UVPDs is largely limited by the relatively high fabrication cost. In this work, we propose a new silicon nanowire (Si NW) UVPD that is very sensitive to UVB light illumination.

Non-Ultrawide Bandgap Semiconductor GaSe Nanobelts for Sensitive Deep Ultraviolet Light Photodetector Application.

In this paper, the authors report the fabrication of a sensitive deep ultraviolet (DUV) photodetector by using an individual GaSe nanobelt with a thickness of 52.1 nm, which presents the highest photoresponse at 265 nm illumination with a responsivity and photoconductive gain of about 663 A W and 3103 at a 3 V bias, respectively, comparable to or even better than other reported devices based on conventional wide bandgap semiconductors. According to the simulation, this photoelectric property is associated with the wavelength-dependent absorption coefficient of the GaSe crystal, for which incident light with shorter wavelengths will be absorbed near the surface, while light with longer wavelengths will have a larger penetration depth, leading to a blueshift of the absorption edge with decreasing thickness.

Spectral Engineering of InSe Nanobelts for Full-Color Imaging by Tailoring the Thickness.

In this work, we report on the synthesis of InSe nanobelts through a catalyst-free chemical vapor deposition (CVD) growth approach. A remarkable blue shift of the peak photoresponse was observed when the thickness of the InSe nanobelt decreases from 562 to 165 nm. Silvaco Technology Computer Aided Design (TCAD) simulation reveals that such a shift in spectral response should be ascribed to the wavelength-dependent absorption coefficient of InSe, for which incident light with shorter wavelengths will be absorbed near the surface, while light with longer wavelengths will have a greater penetration depth, leading to a red shift of the absorption edge for thicker nanobelt devices.

Leaky Mode Resonance-Induced Sensitive Ultraviolet Photodetector Composed of Graphene/Small Diameter Silicon Nanowire Array Heterojunctions.

Ultraviolet photodetectors (UVPDs) based on wide band gap semiconductors (WBSs) are important for various civil and military applications. However, the relatively harsh preparation conditions and the high cost are unfavorable for commercialization. In this work, we proposed a non-WBS UVPD by using a silicon nanowire (SiNW) array with a diameter of 45 nm as building blocks.

Filterless Discrimination of Wavelengths in the Range from Ultraviolet to Near-Infrared Light Using Two PdSe/Thin Si/PdSe Heterojunction Photodetectors.

In this study, we present a wavelength sensor that is capable of distinguishing the spectrum in the range from ultraviolet (UV) to near-infrared (NIR) light. The filterless device is composed of two horizontally stacking PdSe/20 μm Si/PdSe heterojunction photodetectors with a photovoltaic (PV) behavior, which makes it possible for the device to work at 0 bias voltage. Due to the relatively small thickness of Si and the wavelength-dependent absorption coefficient, the two PdSe/20 μm Si/PdSe photodetectors according to theoretical simulation display a sharp contrast in distribution of the photoabsorption rate.

Highly Sensitive Ultraviolet and Visible Wavelength Sensor Composed of Two Identical Perovskite Nanofilm Photodetectors.

This work reports the design of a wavelength sensor composed of two identical perovskite (FA Cs PbI ) photodetectors (PDs) that are capable of discriminating incident wavelength in a quantitative way. Due to strong wavelength-dependent absorption coefficient, the penetration depth of the photons in the FA Cs PbI nanofilms increases with the increasing wavelength, leading to a gradual decrease of photo-generated current for PD1, but an increase of photocurrent in PD2, according to the theoretical simulation of Technology Computer Aided Design. This special evolution of photo-generated current as a function of wavelength facilitates the quantitative determination of the wavelength since the current ratio of both PDs monotonously decreases with the increase of wavelength from 265 to 810 nm.

Low-temperature architecture of a cubic-phase CsPbBr single crystal for ultrasensitive weak-light photodetectors.

We present the first report of a water-regulated method for obtaining a cubic-phase CsPbBr3 single crystal that could be frozen at low temperature with a CsBr/PbBr2 ratio of 1 : 1. The cubic CsPbBr3 single-crystal photodetector exhibits a superior responsivity of 278 A W-1, an EQE of 6.63 × 104%, and an ultrahigh detectivity of 4.

Correction: Construction of PtSe/Ge heterostructure-based short-wavelength infrared photodetector array for image sensing and optical communication applications.

Correction for 'Construction of PtSe2/Ge heterostructure-based short-wavelength infrared photodetector array for image sensing and optical communication applications' by Yu Lu et al., Nanoscale, 2021, 13, 7606-7612, DOI: 10.1039/D1NR00333J.

Construction of PtSe/Ge heterostructure-based short-wavelength infrared photodetector array for image sensing and optical communication applications.

In this work, we present the construction of a multilayered PtSe2/Ge heterostructure-based photodetector array comprising 1 × 10 device units operating in the short-wavelength infrared (SWIR) spectrum region. The as-fabricated heterostructures show an obvious photovoltaic effect, providing the devices with the ability to work as self-driven photodetectors. Upon 1550 nm illumination, a typical photodetector exhibits prominent photoresponse performance with the current on/off ratio, responsivity, external quantum efficiency and specific detectivity reaching 1.

Fabrication of Addressable Perovskite Film Arrays for High-Performance Photodetection and Real-Time Image Sensing Application.

Patterned growth of periodic perovskite film arrays is essential for application in sensing devices and integrated optoelectronic systems. Herein, we report on patterned growth of addressable perovskite photodetector arrays through an uncured polydimethylsiloxane (PDMS) oligomer-assisted solution-processed approach, in which a periodic hydrophilic/hydrophobic substrate replicating the predesigned patterns of the PDMS stamp was formed due to the migration of uncured siloxane oligomers in the PDMS stamp to the intimately contacted substrate. By using this technique, MAPbI film photodetector arrays with neglectable pixel-to-pixel variation, a responsivity of 2.

Direct Tellurization of Pt to Synthesize 2D PtTe for High-Performance Broadband Photodetectors and NIR Image Sensors.

Platinum telluride (PtTe) has garnered significant research enthusiasm owing to its unique characteristics. However, large-scale synthesis of PtTe toward potential photoelectric and photovoltaic application has not been explored yet. Herein, we report direct tellurization of Pt nanofilms to synthesize large-area PtTe films and the influence of growth conditions on the morphology of PtTe.

High-Performance Deep Ultraviolet Photodetector Based on a One-Dimensional Lead-Free Halide Perovskite CsCuI Film with High Stability.

Lead halide perovskites have received much attention in the field of optoelectronic devices. However, the environment-unfriendly nature and intrinsic instability of these perovskites hamper their commercial applications. In this work, one novel one-dimensional lead-free halide perovskite with high stability, CsCuI, was prepared via an antisolvent-assisted crystallization method.

Self-Powered Filterless Narrow-Band p-n Heterojunction Photodetector for Low Background Limited Near-Infrared Image Sensor Application.

Photonic detection with narrow spectrum selectivity is very important to eliminate the signal from obtrusive light, which can improve the anti-interference ability of the infrared imaging system. While the self-driving effect inherent to the p-n junction is very attractive in optic-electronic integration, the application of the p-n junction in narrow-band photodetectors is limited by the usual broad absorption range. In this work, a self-powered filterless narrowband near-infrared photodetector based on CuGaTe/silicon p-n junction was reported.

Ultrathin Polymer Nanofibrils for Solar-Blind Deep Ultraviolet Light Photodetectors Application.

Solar-blind deep ultraviolet photodetectors (DUVPDs) based on conventional inorganic ultrawide bandgap semiconductors (UWBS) have shown promising application in various civil and military fields and yet they can hardly be used in wearable optoelectronic devices and systems for lack of mechanical flexibility. In this study, we report a non-UWBS solar-blind DUVPD by designing ultrathin polymer nanofibrils with a virtual ultrawide bandgap, which was obtained by grafting P3HT with PHA via a polymerization process. Optoelectronic analysis reveals that the P3HT--PHA nanofibrils are sensitive to DUV light with a wavelength of 254 nm but are virtually blind to both 365 nm and other visible light illuminations.

Multilayered PdSe/Perovskite Schottky Junction for Fast, Self-Powered, Polarization-Sensitive, Broadband Photodetectors, and Image Sensor Application.

Group-10 transition metal dichalcogenides (TMDs) with distinct optical and tunable electrical properties have exhibited great potential for various optoelectronic applications. Herein, a self-powered photodetector is developed with broadband response ranging from deep ultraviolet to near-infrared by combining FA Cs PbI perovskite with PdSe layer, a newly discovered TMDs material. Optoelectronic characterization reveals that the as-assembled PdSe/perovskite Schottky junction is sensitive to light illumination ranging from 200 to 1550 nm, with the highest sensitivity centered at ≈800 nm.

Light Confinement Effect Induced Highly Sensitive, Self-Driven Near-Infrared Photodetector and Image Sensor Based on Multilayer PdSe /Pyramid Si Heterojunction.

In this study, a highly sensitive and self-driven near-infrared (NIR) light photodetector based on PdSe /pyramid Si heterojunction arrays, which are fabricated through simple selenization of predeposited Pd nanofilm on black Si, is demonstrated. The as-fabricated hybrid device exhibits excellent photoresponse performance in terms of a large on/off ratio of 1.6 × 10 , a responsivity of 456 mA W , and a high specific detectivity of up to 9.

Sensitive Deep Ultraviolet Photodetector and Image Sensor Composed of Inorganic Lead-Free CsCuI Perovskite with Wide Bandgap.

In this work, a sensitive deep ultraviolet (DUV) light photodetector based on inorganic and lead-free CsCuI crystalline film derived by a solution method was reported. Optoelectronic characterization revealed that the perovskite device exhibited nearly no sensitivity to visible illumination with wavelength of 405 nm but exhibited pronounced sensitivity to both DUV and UV light illumination with response speeds of 26.2/49.

Opening the Band Gap of Graphene via Fluorination for High-Performance Dual-Mode Photodetector Application.

Fluorination is an effective process to open the band gap of graphene (Gr), which is beneficial to the development of optoelectronic devices working in wide wavelength. Herein, we report a dual-mode broadband photodetector (PD) by integrating fluorinated graphene (F-Gr) with silicon (Si). It is found that when working in photoconductive mode, the F-Gr/Si heterojunction exhibited a remarkable photoresponse over a wide spectral region from ultraviolet (UV), visible to near infrared (NIR) light with a high responsivity ( R) of 1.

Graphene-Assisted Growth of Patterned Perovskite Films for Sensitive Light Detector and Optical Image Sensor Application.

Controlled growth of high-quality patterned perovskite films on a large scale is essentially required for the application of this class of materials in functional integrated devices and systems. Herein, graphene-assisted hydrophilic-hydrophobic surface-induced growth of Cs-doped FAPbI perovskite films with well-patterned shapes by a one-step spin-coating process is developed. Such a facile fabrication technique is compatible with a range of spin-coated perovskite materials, perovskite manufacturing processes, and substrates.

High-Performance Photocoupler Based on Perovskite Light Emitting Diode and Photodetector.

Photocoupler is a kind of semiconductor optoelectronic device that integrates light-emitting device (LED) and photodetector. It has found wide application in various fields because of its capability to transmit the electrical signal through the conversion of the electricity-light-electricity. Herein, we report the fabrication of a new photocoupler by simply integrating perovskite quantum dots LED and perovskite photodetector on a glass substrate.

Dual-plasmonic Au/graphene/Au-enhanced ultrafast, broadband, self-driven silicon Schottky photodetector.

High-performance photodetectors are desirable for various applications, including multi-wavelength image sensing, communication, and safety monitoring. In this study, we report the construction of a dual-surface plasmon-enhanced silicon Schottky photodetector using Au nanoparticles (NPs)/graphene/Au NPs hybrid structure as the electrode. It was found that the as-assembled device exhibited broad sensitivity, ranging from ultraviolet to near-infrared light (360-1330 nm) at room temperature, with a high response speed of 360 ns and a 3 dB bandwidth of 780 kHz at zero bias.

Mesoporous anodic α-FeO interferometer for organic vapor sensing application.

In this work, we reported the utilization of mesoporous α-FeO films as optical sensors for detecting organic vapors. The mesoporous α-FeO thin films, which exhibited obvious Fabry-Perot interference fringes in the reflectance spectrum, were successfully fabricated through electrochemical anodization of Fe foils. Through monitoring the optical thickness of the interference fringes, three typical organic species with different vapor pressures and polarities (hexane, acetone and isopropanol) were applied as probes to evaluate the sensitivity of the α-FeO based interferometric sensor.