Due to its lead-free composition and a unique double polarization hysteresis loop with a large maximum polarization (P max ) and a small remnant polarization (P r ), AgNbO 3 -based antiferroelectrics (AFEs) have attracted extensive research interest for electric energy storage applications. However, a low dielectric breakdown field (E b ) limits an energy density and its further development. In this work, a highly efficient method was proposed to fabricate high-energy-density Ag(Nb,Ta)O 3 capacitor films on Si substrates, using a two-step process combining radio frequency (RF)-magnetron sputtering at 450 ℃ and post-deposition rapid thermal annealing (RTA). The RTA process at 700 ℃ led to sufficient crystallization of nanograins in the film, hindering their lateral growth by employing short annealing time of 5 min. The obtained Ag(Nb,Ta)O 3 films showed an average grain size (D) of ~14 nm (obtained by Debye-Scherrer formula) and a slender room temperature (RT) polarization-electric field (P-E) loop (P r ≈ 3.8 C•cm −2 and P max ≈ 38 C•cm −2 under an electric field of ~3.3 MV•cm −1 ), the P-E loop corresponding to a high recoverable energy density (W rec ) of ~46.4 J•cm −3 and an energy efficiency (η) of ~80.3%. Additionally, by analyzing temperature-dependent dielectric property of the film, a significant downshift of the diffused phase transition temperature (T M2-M3 ) was revealed, which indicated the existence of a stable relaxor-like † Hongbo Cheng and Xiao Zhai contributed equally to this work.

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The microwave wireless power transfer is a power transmission device that breaks through the limitation of the transmission line, and is helpful for handling equipment power supply problems in complex scenes. Thus, it has a wide array of applications. This paper focuses on the research and design of the core components of the receiving part of the microwave wireless power transfer, it optimizes the material physical parameters and geometrical parameters of the device to improve the energy conversion efficiency. First, we using the ADS simulation tool, the relationship between the electrical parameters of the schottky diode and the energy conversion efficiency is obtained by adjusting the SPICE parameters of the schottky diode. The optimal design principle is proposed, which lays a theoretical foundation for the optimization design of the subsequent high energy conversion efficiency rectifier device. Second, basing on the diode rectification principle and the theoretical basis obtained in the first part, a GeSn folded space charge on the insulating layer is proposed. Using the device simulation tool Silvaco to adjust the physical parameters of the device material and the geometrical parameters, the device structure of the GeSnOI folded space charge region Schottky diode is obtained. The results show that compared with the traditional structure Ge schottky diode, the folded space charge region schottky diode optimized in this paper has the advantage of significantly improving its energy conversion efficiency, and the energy conversion efficiency is improved by 8.1%. INDEX TERMS Microwave wireless power transfer (MWPT), GeSnOI, schottky diode, energy conversion efficiency, folded space charge region.

Ge Schottky diode is the core component of the rectifier circuit in wireless power transfer. By reducing its series resistance, the rectification efficiency of the wireless power transfer can be improved. Ge can be made into a direct band gap semiconductor by alloying with 8% Sn component or 3% Pb component. The electron mobility of direct band gap Ge 1-x Y x (Sn, Pb) alloy is two to three times that of Ge. High electron mobility will reduce the series resistance of a Schottky diode. Therefore, in recent years, direct band-gap Ge 1-x Y x (Sn, Pb) alloys for Schottky diodes have attracted much more attention. Using a direct band gap Ge 1-x Y x (Sn, Pb) alloy to make a Schottky diode requires designing a Schottky junction first. To this end, the first-principle method is used to calculate Ge 1-x Y x (Sn, Pb) alloys along different directions, which provides a theoretical basis for the subsequent Schottky junction design.

Gear’s pulse electrochemical finishing (PECF) technology by shaped electrodes based on the numeral control technology, which controls gear dividing device and feed movement, is put forwards. Based on numerical simulation, electrochemical reaction region is dispersed. According to gear tooth profile and negative electrode surface equations, boundary conditions are inferred. The numerical simulation of the electric potential distribution in the calculation region has been shown. Under the optimized parameters, a mirror-like surface of gear teeth could be gained by PECF. The results show PECF can fulfill the advantages in the finishing some special gears with hard teeth.