Charge-triggered switching mechanism in selenium selector enabling ultralow leakage current

Nature Materials (2026)Cite this article The rapid growth of artificial intelligence models has outpaced the capabilities of current dynamic random-access memory/flash storage systems in speed, density and energy efficiency. Three-dimensional phase-change memory offers a scalable solution, yet cross-point integration is limited by selector performance. Here, by reverse-tracing previously reported ovonic threshold switch (OTS) materials, we identify amorphous elemental selenium as a highly effective OTS selector. It exhibits an ultralow leakage current (4 × 10−12 A), an on/off current ratio exceeding 108, high drive current density (21.2 MA cm−2), fast switching speed (~20 ns) and endurance up to 2 × 109 cycles. Photoexcitation spectroscopy and density functional theory calculations reveal a charge-triggered mechanism: dense trap pairs in amorphous selenium strongly pin the Fermi level and suppress leakage, while full carrier excitation in these traps near threshold, together with impact-ionization-induced avalanche multiplication, enables abrupt switching and high on-current. Integrated selenium-selector/phase-change memory arrays demonstrate reliable write/erase operations with a 0.75-V read margin. These results clarify the OTS mechanism and establish amorphous selenium as a leading selector material for three-dimensional memory.This is a preview of subscription content, access via your institution Access Nature and 54 other Nature Portfolio journals Get Nature+, our best-value online-access subscription $32.99 / 30 days cancel any timeSubscribe to this journal Receive 12 print issues and online access $259.00 per yearonly $21.58 per issueBuy this articleUSD 39.95Prices may be subject to local taxes which are calculated during checkoutThe data supporting the findings of this study are available within the article and its Supplementary Information. 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