Impact of Silicon Doping on the Structural and Electronic Properties of Amorphous Germanium Sulfide for Ovonic Threshold Switching Selector

Amorphous germanium sulfide(a‐GeS) holds significant promise as a threshold‐switching selector material for three‐dimensional crossbar memory applications. In this study, we employ ab initio molecular dynamics simulations to investigate the effects of silicon (Si) doping on the structural and electronic properties of a‐GeS, aiming to enhance its ovonic threshold switching (OTS) performance. Our results reveal that Si doping leads to the formation of strong SiSi and SiS bonds within the amorphous network. Si‐centered clusters predominantly adopt tetrahedral configurations, and the fraction of Ge‐centered tetrahedra also increases, contributing to enhanced structural stability. Furthermore, the mobility gap narrows in Si‐doped a‐GeS (a‐SiGeS), while the mid‐gap states increase, enabling it to still maintain a relatively high threshold voltage. Importantly, atomic mobility is significantly suppressed in a‐SiGeS, which is expected to improve cycling endurance. These findings highlight Si doping as an effective strategy for tailoring the performance of amorphous chalcogenide selectors, positioning a‐SiGeS as a promising material candidate for high‐density nonvolatile memory.