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.