Defect engineering in sulfur-doped two-dimensional SnSe for enhanced memristive performance

Defects strongly influence the mechanical, optical, and particularly the electrical properties of two-dimensional (2D) materials and they may be engineered to enhance their performance. Herein, 2D S-doped SnSe (SnSe 1 − x S x , x  = 0, 0.25, 0.5, 0.75) is obtained via chemical vapor deposition (CVD) and used to fabricate Ag/SnSe 1− x S x /Pt memristors. The density of doping-induced defects increases and then decreases with the increasing S content ( x ), strongly impacting the electrical properties of SnSe 1− x S x . The memristor switching mechanism changes from anion (vacancy) transport at x  = 0 to primarily cation migration at x  = 0.25, anion and cation migration at x  = 0.5, and mainly anion (vacancy) migration at x  = 0.75. Optimal S doping ( x  = 0.25) enhances the ability of SnSe to retain its advantageous electrical properties at high temperatures, and the corresponding memristor exhibits stable operation within the temperature range of 150 - 175 °C.