Crossbar array provides a cost-effective approach for achieving high-density integration of two-terminal functional devices. However, the "sneaking current problem", which can lead to read failure, is a severe challenge in crossbar arrays. To inhibit the sneaking current from unselected cells, the integration of individual selection devices is necessary. In this work, we report a novel TaO_x-based selector exhibiting a trapezoidal band structure formed by tuning the concentration of defects in the oxide. Salient features such as a high current density (1 MA·cm^–2), high selectivity (5 × 10⁴), low off-state current (~10 pA), robust endurance (> 10¹⁰), self-compliance, and excellent uniformity were successfully achieved. The integrated one-selector one-resistor (1S1R) device exhibits high nonlinearity in the low resistance state (LRS), which is quite effective in solving the sneaking current issue.

The charge-trapping process, with HfO₂ film as the charge-capturing layer, has been investigated by using in situ electron energy-loss spectroscopy and in situ energy-filter image under positive external bias. The results show that oxygen vacancies are non-uniformly distributed throughout the HfO₂ trapping layer during the programming process. The distribution of the oxygen vacancies is not the same as that of the reported locations of the trapped electrons, implying that the trapping process is more complex. These bias-induced oxygen defects may affect the device performance characteristics such as the device lifetime. This phenomenon should be considered in the models of trapping processes.

Arrays of low-dimensional molecular crystals of square columns (1-D) and nanolamellae (2-D) of Zn[TCNQ]₂(H₂O)₂ with large areas (up to 10–20 cm²) have been synthesized by controlled addition of water to Zn and TCNQ. Based on the ability to accurately control the reaction, a new moisture and water indicator has been developed. The simple method, the large areas of material prepared, the fine size tuning, and the typical semiconductor behavior of the resulting low-dimensional molecular materials promise applications in molecular electronics as well as nanoelectronics. The system is an effective indicator for the detection of traces of water and moisture.