A planar lateral vacuum field emission triode (VFET) with a nanoscale channel of 80–90 nm was fabricated on a silicon wafer. The nanoscale channel of this vacuum triode was generated by via the electro-forming process (EFP). With the use of a wedge-waist-type conductive film, the distribution of Joule heat during EFP could be guided, which helped to realize the controllable preparation of a nanoscale fissure that served as the vacuum channel. Experimental results revealed that the fabricated device demonstrated good emission characteristics in vacuum and could be operated normally under atmospheric conditions. The triode emission characteristics under atmospheric pressure were preliminarily realized. The field-assisted thermal electron emission for low operating voltage and the Fowler–Nordheim tunneling emission mechanism for voltages greater than the turn-on voltage were used to explain the emission mechanism of the proposed VFET.

SnO₂ has attracted much attention due to its low-temperature synthesis (ca. 140 °C), high electron mobility, and low-cost manufacturing. However, lattice mismatch and oxygen vacancies at the SnO₂/CsPbI_3−xBr_x interface generally lead to undesirable nonradiative recombination in optoelectronic devices. The traditional TiO₂ used as the electron transport layer (ETL) for all-inorganic perovskite solar cells (PSCs) requires high-temperature sintering and crystallization, which are not suitable for the promising flexible PSCs and tandem solar cells, raising concerns about surface defects and device uniformity. To address these challenges, we present a bilayer ETL consisting of a SnO₂ layer using electron beam evaporation and a TiO₂ layer through the hydrothermal method, resulting in an enhanced performance of the perovskite solar cell. The bilayer device exhibits an improved power conversion efficiency of 11.48% compared to the single-layer device (8.09%). The average fill factor of the bilayer electron transport layer is approximately 15% higher compared to the single-layer electron transport layer. Through a systematic investigation of the use of ETL for CsPb_3−xBr_x PSCs on optical and electronic properties, we demonstrate that the SnO₂/TiO₂ is an efficient bilayer ETL for PSCs as it significantly enhances the charge extraction capability, suppresses carrier recombination at the ETL/perovskite interface, facilitates efficient photogenerated carrier separation and transport, and provides high current density and reduced hysteresis.

A planar lateral Vacuum Field Emission Triode (VFET) with a double gate structure is proposed to improve the gate modulation characteristics in this letter. The preparation of this double gate structure is obtained by using the mature bottom gate VFET manufacturing process without any additional dedicated masks. The emission characteristics of the fabricated VFET under vacuum and atmosphere condition are measured. The experimental results demonstrate that both the bottom gate and the top gate can effectively control the emission electrons in the vacuum channel with width of about 110–200 nm which is successfully prepared by the electro-forming process. The operating mechanism of the device is basically the same as that of the plane-bottom gate VFET, and the device has achieved good field electron emission characteristics and double-gate modulation characteristics. Meanwhile, the vacuum channel is covered by the top gate insulator layer, which relaxing the vacuum requirement and improving the collection efficiency of emitted electrons by drain electrode about 50% in air.

IGZO thin films can be used as active layers of thin-film transistors and have been widely studied. However, amorphous indium gallium zinc oxide (IGZO) fabricated at room temperature is vulnerable in subsequent manufacturing processes, such as etching and sputtering; this limits IGZO thin film transistors’ (TFTs) use in commercial products. In this paper, we prepared a c-axis crystallized IGZO thin film by Radio Frequency (RF) sputtering at 180 °C, with a 50% O₂ ratio and 110 W power. XRD images show that the crystallized film has an obvious diffraction peak near 31°, and the spacing between the crystal surfaces was calculated to be ≈0.29 nm. The HRTEM map confirmed the above results. The stability of IGZO thin films was investigated by etching them with an acid solution. The crystalline IGZO films exhibited better acid corrosion resistance, and their anticorrosion performance was 74% higher than that of amorphous IGZO (a-IGZO) films, indicating the crystalline IGZO film can provide more stable performance in applications.

Electron transport layer (ETL) plays an undeniable role in improving the performance of n-i-p planar perovskite solar cells (PSCs). Titanium dioxide (TiO₂) is known as a promising ETL material for perovskite solar cell. In this work, the effect of annealing temperature on optical, electrical, and surface morphology of the electron-beam (EB)-evaporated TiO₂ ETL, and consequently on the performance of perovskite solar cell, was investigated. It was found that annealing treatment at an optimized temperature of 480 °C considerably improved the surface smoothness, density of grain boundaries, and carrier mobility of TiO₂ film, which resulted in nearly 10-fold improvement in power conversion efficiency (11.16%) in comparison with the unannealed device (1.08%). The improvement in performance of the optimized PSC is attributed to the acceleration of charge carrier extraction, as well as suppression of the recombination at the ETL/Perovskite interface.