Pressure-Induced Bandgap Engineering and Photoresponse Enhancing of Wurtzite CuInS2 Nanocrystals

Wurtzite CuInS2 exhibits great potential for optoelectronic applications because of its excellent optical properties and good stability. However, exploring effective strategy to simultaneously optimaze its optical and photoelectrical properties remains...

Simply equipped ε-Ga2O3 film/ZnO nanoparticle heterojunction for self-powered deep UV sensor

In this paper, a ε-Ga2O3 film/ZnO nanoparticle hybrid heterojunction deep ultraviolet (UV) photodetector is described for 254 nm wavelength sensing application. The constructed ε-Ga2O3/ZnO heterojunction photodetector can operate in dual modes which are power supply mode and self-powered mode. Under reverse 5 V bias with 254 nm light intensity of 500 μW/cm2, the photoresponsivity, specific detectivity and external quantum efficiency are 59.7 mA/W, 7.83×1012 Jones and 29.2%. At zero bias, the advanced ε-Ga2O3/ZnO photodetector performs decent self-powered photoelectrical properties with photo-to-dark current ratio of 1.28×105, on/off switching ratio of 3.22×104, rise/decay times of 523.1/31.7 ms, responsivity of 4.12 mA/W and detectivity of 2.24×1012 Jones. The prominent photodetection performance lays a solid foundation for ε-Ga2O3/ZnO heterojunction in deep UV sensor application.

FIB-Assisted Fabrication of Single Tellurium Nanotube Based High Performance Photodetector

Nanoscale tellurium (Te) materials are promising for advanced optoelectronics owing to their outstanding photoelectrical properties. In this work, high-performance optoelectronic nanodevice based on a single tellurium nanotube (NT) was prepared by focused ion beam (FIB)-assisted technique. The individual Te NT photodetector demonstrates a high photoresponsivity of 1.65 × 104 AW−1 and a high photoconductivity gain of 5.0 × 106%, which shows great promise for further optoelectronic device applications.

Light-activated Multilevel Resistive Switching Storage in Pt/Cs2AgBiBr6/ITO/Glass Devices

High-density Cs2AgBiBr6 films with uniform grains were prepared by a simple one-step and low-temperature sol–gel method on indium tin oxide (ITO) substrates. An explicit tristate bipolar resistance switching behavior was observed in the Pt/Cs2 AgBiBr6/ITO/glass devices under irradiation of 10 mW/cm2 (445 nm). This behavior was stable over 1200 s. The maximum ratio of the high and low resistance states was about 500. Based on the analysis of electric properties, valence variation and absorption spectra, the resistive switching characteristics were attributed to the trap-controlled space charge-limited current mechanism due to the bromine vacancies in the Cs2AgBiBr6 layer. On the other hand, it is suggested that the ordering of the Schottky-like barrier located at Pt/Cs2AgBiBr6 affects the three-state resistance switching behavior under light irradiation. The ability to adjust the photoelectrical properties of Cs2AgBiBr6-based resistive switching memory devices is a promising strategy to develop high-density memory. Graphical Abstract

Photoactivation of Cell-Free Expressed Archaerhodopsin-3 in a Model Cell Membrane

Transmembrane receptor proteins are located in the plasma membranes of biological cells where they exert important functions. Archaerhodopsin (Arch) proteins belong to a class of transmembrane receptor proteins called photoreceptors that react to light. Although the light sensitivity of proteins has been intensely investigated in recent decades, the electrophysiological properties of pore-forming Archaerhodopsin (Arch), as studied in vitro, have remained largely unknown. Here, we formed unsupported bilayers between two channels of a microfluidic chip which enabled the simultaneous optical and electrical assessment of the bilayer in real time. Using a cell-free expression system, we recombinantly produced a GFP (green fluorescent protein) labelled as a variant of Arch-3. The label enabled us to follow the synthesis of Arch-3 and its incorporation into the bilayer by fluorescence microscopy when excited by blue light. Applying a green laser for excitation, we studied the electrophysiological properties of Arch-3 in the bilayer. The current signal obtained during excitation revealed distinct steps upwards and downwards, which we interpreted as the opening or closing of Arch-3 pores. From these steps, we estimated the pore radius to be 0.3 nm. In the cell-free extract, proteins can be modified simply by changing the DNA. In the future, this will enable us to study the photoelectrical properties of modified transmembrane protein constructs with ease. Our work, thus, represents a first step in studying signaling cascades in conjunction with coupled receptor proteins.

Fabrication of Large-Area Molybdenum Disulfide Device Arrays Using Graphene/Ti Contacts

Two-dimensional (2D) molybdenum disulfide (MoS2) is the most mature material in 2D material fields owing to its relatively high mobility and scalability. Such noticeable properties enable it to realize practical electronic and optoelectronic applications. However, contact engineering for large-area MoS2 films has not yet been established, although contact property is directly associated to the device performance. Herein, we introduce graphene-interlayered Ti contacts (graphene/Ti) into large-area MoS2 device arrays using a wet-transfer method. We achieve MoS2 devices with superior electrical and photoelectrical properties using graphene/Ti contacts, with a field-effect mobility of 18.3 cm2/V∙s, on/off current ratio of 3 × 107, responsivity of 850 A/W, and detectivity of 2 × 1012 Jones. This outstanding performance is attributable to a reduction in the Schottky barrier height of the resultant devices, which arises from the decreased work function of graphene induced by the charge transfer from Ti. Our research offers a direction toward large-scale electronic and optoelectronic applications based on 2D materials.