In this study, a Pt/Ag/LZO/Pt resistive random access memory (RRAM), doped by different Li-doping concentrations was designed and fabricated by using a magnetron sputtering method. To determine how the Li-doping concentration affects the crystal lattice structure in the composite ZnO thin films, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) tests were carried out. The resistive switching behaviors of the resulting Pt/Ag/LZO/Pt devices, with different Li-doping contents, were studied under direct current (DC) and pulse voltages. The experimental results showed that compared with the devices doped with Li-8% and -10%, the ZnO based RRAM device doped by 5% Li-doping presented stable bipolar resistive switching behaviors with DC voltage, including a low switching voltage (10³ cycles), long retention time (>10⁴ s), and a large resistive switching window. In addition, quick switching between a high-resistance state (HRS) and a low-resistance state (LRS) was achieved at a pulse voltage. To investigate the resistive switching mechanism of the device, a conduction model was installed based on Ag conducting filament transmission. The study of the resulting Pt/Ag/LZO/Pt devices makes it possible to further improve the performance of RRAM devices.

In order to improve the output sensitivity of the piezoelectric acceleration sensor, this paper proposed a high sensitivity acceleration sensor based on a piezoelectric metal oxide semiconductor field effect transistor (MOSFET). It is constituted by a piezoelectric beam and an N-channel depletion MOSFET. A silicon cantilever beam with Pt/ZnO/Pt/Ti multilayer structure is used as a piezoelectric beam. Based on the piezoelectric effect, the piezoelectric beam generates charges when it is subjected to acceleration. Due to the large input impedance of the MOSFET, the charge generated by the piezoelectric beam can be used as a gate control signal to achieve the purpose of converting the output charge of the piezoelectric beam into current. The test results show that when the external excitation acceleration increases from 0.2 g to 1.5 g with an increment of 0.1 g, the peak-to-peak value of the output voltage of the proposed sensors increases from 0.327 V to 2.774 V at a frequency of 1075 Hz. The voltage sensitivity of the piezoelectric beam is 0.85 V/g and that of the proposed acceleration sensor was 2.05 V/g, which is 2.41 times higher than the piezoelectric beam. The proposed sensor can effectively improve the voltage output sensitivity and can be used in the field of structural health monitoring.

In this paper, a double piezoelectric layer acceleration sensor based on Li-doped ZnO (LZO) thin film is presented. It is constituted by Pt/LZO/Pt/LZO/Pt/Ti functional layers and a Si cantilever beam with a proof mass. The LZO thin films were prepared by radio frequency (RF) magnetron sputtering. The composition, chemical structure, surface morphology, and thickness of the LZO thin film were analyzed. In order to study the effect of double piezoelectric layers on the sensitivity of the acceleration sensor, we designed two structural models (single and double piezoelectric layers) and fabricated them by using micro-electro-mechanical system (MEMS) technology. The test results show that the resonance frequency of the acceleration sensor was 1363 Hz. The sensitivity of the double piezoelectric layer was 33.1 mV/g, which is higher than the 26.1 mV/g of single piezoelectric layer sensitivity, both at a resonance frequency of 1363 Hz.

Write-once-read-many-times (WORM) memory belonging to an important non-volatile memory type achieves the read-only state after the write operation and is used in the fields of data security storage widely. WORM memory has been developed based on a variety of materials. In recent years, halide perovskites have become the research hotspot material for this memory due to its excellent properties. Here, the all-inorganic CsPbBr₃ perovskite thin film was prepared on a FTO substrate by using a two-step method. The prepared CsPbBr₃ thin films have the characteristics of densely packed crystal grains and smooth surface. The device, having the FTO/CsPbBr₃/Al sandwich structure by evaporating the Al electrode onto the CsPbBr₃ thin film, represents the typical WORM behavior, with long data retention time (10⁴ s), a low operation voltage (2.1 V) and a low reading voltage (0.1 V). Additionally, the resistance transition mechanism of the resulting WORM devices was analyzed.

Nonlinear correction was performed on the mechanical motion of ultra-thin cantilever beams, and strain effects were calculated on ultra-thin multi-layer heterogeneous material stacked cantilever beams. The atomic structure and piezoelectric properties of ZnO were studied using first-principles calculations. In this study, generalized gradient approximations of Perdew–Burke–Erzerhof (GGA-PBE) functionals and Plain Wave Basis Sets were used to calculate the electronic structure, density of states, energy bands, charge density, and piezoelectric coefficient of intrinsic ZnO. Research and calculations were conducted on Li-doped ZnO with different ratios. According to our calculations, as the Li doping ratio increases from 0 to 10%, the bandgap width of ZnO material increases from 0.74 to 1.21 eV. The results for the density of states and partial density of states indicate that the increase in band gap is due to the movement of Zn-3d states towards the high-energy end, and the piezoelectric coefficient of the material increases from 2.07 to 3.3 C/m². Meanwhile, based on the optimized Li-doped ZnO cantilever beam accelerometer, an ultra-thin cantilever beam accelerometer with a sensitivity of 7.04 mV/g was fabricated.