We report the structure, optical, and gas-sensing properties of ZnO nanorods with different diameters. Vertically well-aligned homogeneous nanorods were grown along the c-axis orientation. The shift of Raman scattering E 2 (high) mode and photoluminescence (PL) spectra were used to study the dependences of nanorod diameters on the stress and oxygen vacancy. Gas sensors were prepared and tested for the detection of C 2 H 5 OH and H 2 S (100 ppm) in air. It was found that the thin nanorods have a significantly better sensing performance than the thick nanorods. We provide a possible explanation from the aspect of the sensing mechanism of the surface reaction process.

In this letter, we present a gas sensor using a single ZnO nanowire as a sensing unit. This ZnO nanowire-based sensor has quick and high sensitive response to H2S in air at room temperature. It has also been found that the gas sensitivity of the ZnO nanowires could be modulated and enhanced by He+ implantation at an appropriate dose. A possible explanation is given based on the modulation model of the depletion layer.

A MoS2 nanosphere memristor with lateral gold electrodes was found to show photoresistive switching. The new device can be controlled by the polarization of nanospheres, which causes resistance switching in an electric field in the dark or under white light illumination. The polarization charge allows to change the switching voltage of the photomemristor, providing its multi-level operation. The device, polarized at a voltage 6 V, switches abruptly from a high resistance state (HRSL6) to a low resistance state (LRSL6) with the On/Off resistance ratio of about 10 under white light and smooth in the dark. Analysis of device conductivity in different resistive states indicates that its resistive state could be changed by the modulation of the charge in an electric field in the dark or under light, resulting in the formation/disruption of filaments with high conductivity. A MoS2 photomemristor has great potential as a multifunctional device designed by using cost-effective fabrication techniques.

Oxygen evolution reaction (OER) is an obstacle to the electrocatalytic water splitting due to its unique four‐proton‐and‐electron‐transfer reaction process. Many methods, such as engineering heterostructure and introducing oxygen vacancy, have been used to improve the catalytic performance of electrocatalysts for OER. Herein, the above two kinds of regulation are simultaneously realized in a catalyst by using unique ion irradiation technology. A nanosheet structured NiO/NiFe2O4 heterostructure with rich oxygen vacancies converted from nickel–iron layered double hydroxides by Ar+ ions irradiation shows significant enhancement in both OER and hydrogen evolution reaction performance. Density functional theory (DFT) calculations reveal that the construction of NiO/NiFe2O4 can optimize the free energy of O* to OOH* process during OER reaction. The oxygen vacancy‐rich NiO/NiFe2O4 nanosheets have an overpotential of 279 mV at 10 mA cm−2 and a low Tafel slope of 42 mV dec−1. Moreover, this NiO/NiFe2O4 electrode shows an excellent long‐term stability at 100 mA cm−2 for 450 h. The synergetic effects between NiO and NiFe2O4 make NiO/NiFe2O4 heterostructure have high conductivity and fast charge transfer, abundant active sites, and high catalytic reactivity, contributing to its excellent performance.

Nanocrystalline (nc) -Si was grown on SiO2 by rapid thermal chemical vapor deposition. The tunneling oxide layer of a thickness of 4 nm was formed on p-type Si(100) by rapid thermal oxidation at 1050 °C for 30 s. Metal–oxide–semiconductor (MOS) structures were fabricated and capacitance–voltage characterization was carried out to study the memory effects of the nc-Si embedded in the MOS structure. We found the memory effect to be dominantly related to hydrogen-related traps, in addition to being influenced by the three-dimensional quantum confinement and Coulomb charge effects. Deep level transient spectroscopy reveal that the activation energies of the hydrogen-related traps are Ev+0.29 eV (H1) and Ev+0.42 eV (H2), and the capture cross sections are 4.70×10−16 cm2 and 1.44×10−15 cm2, respectively. The presence of Si–H and Si–H2 bonds was confirmed by Fourier transform infrared spectroscopy.