Elemental Selector for High-Density Memory Integration

Ovonic threshold switching selectors are indispensable for suppressing sneak currents in dense cross-point memories, but most established selector materials still rely on multicomponent chalcogenides with persistent trade-offs in leakage current, reliability, and compositional stability. Recent progress in elemental switching materials is beginning to change this picture. A new study identifies amorphous selenium as a highly effective selector, combining an ultralow leakage current of 4 × 10^-12 A, an on/off ratio above 10⁸, a drive current density of 21.2 MA cm^-2, nanosecond-scale switching, and endurance up to 2 × 10⁹ cycles. More importantly, spectroscopy and theory connect these metrics to a charge-triggered mechanism rooted in dense trap pairs in the amorphous network. These states strongly pin the Fermi level in the off-state, while field-induced carrier release near threshold drives abrupt conduction. Beyond introducing a new selector material, this work suggests that monatomic chalcogens may provide a cleaner platform for understanding and engineering threshold switching, with fewer complications from phase segregation, cation migration, and chemical overdesign.