Reliable Low-Energy Selector-Only Memory Operation via Sb-Induced Trap-State Modulation in As-/Te-Free Ge2Se3

Selector-only memory (SOM) integrates memory and selector functions within a single volatile threshold-switching layer, offering a compact architecture for high-density cross-point arrays. However, its practical performance depends strongly on the introduction and distribution of trap states in the chalcogenide network. Conventional SOM materials often rely on As- or Te-containing chalcogenides to achieve effective trap-state engineering, but their toxicity, limited stability, and integration challenges motivate the development of safer alternatives. Here, we report Sb-doped Ge2Se3 (Sb(x):GS, where x denotes the Sb atomic fraction) as an As-/Te-free SOM material and investigate the effects of Sb-induced trap-state modulation on low-energy and reliable operation. Pure Ge2Se3 (GS) offers a robust Ge-Se network but insufficient effective trap states for energy-efficient SOM operation; thus, Sb was incorporated to tune the trap distribution and enhance SOM performance. The optimized Sb(0.16):GS device exhibits polarity-dependent threshold voltage (Vth) states of Vth1 ≈ 2.1 V and Vth2 ≈ 4.5 V, corresponding to a large memory window (MW) of approximately 2.4 V, while maintaining a low off-state current of ∼5 nA. Compared to pure GS, Sb(0.16):GS reaches a saturated MW at approximately 33% lower write energy under identical programming conditions and exhibits reliable state separation during repeated switching and drift evaluation. X-ray photoelectron spectroscopy, Raman spectroscopy, optical absorption analysis, and temperature-dependent transport measurements indicate that moderate Sb incorporation preserves the Ge-Se network while introducing Sb-Se-associated trap states that increase the separation between the trap depth and activation energy of the two programmed states. In contrast, excessive Sb incorporation promotes Sb-rich homopolar bonding and broadens the trap distribution, degrading switching performance. The findings provide practical design guidelines for engineering trap states in chalcogenide selectors and advance the development of energy-efficient, reliable, and high-density SOM technologies.