Low-Field Memristive Switching in Epitaxially Strained SnS Thin Film

Abstract

The quasi van der Waals (vdW) polarizable semiconductor, tin monosulfide (SnS), holds exceptional potential as a memristor in neuromorphic architectures as well as for sustainable, mechanically flexible and biocompatible photovoltaic and piezoelectric applications. So far, the synthesis of SnS remained limited to flake scale growth or subject to a compromise between substrate interaction and crystal order. In this work, this limitation is overcame by introducing a substrate pretreatment with reactive sulfur to a hybrid chemical/physical growth method. This approach achieves the sharply interfaced growth of a textured epitaxial SnS thin film directly on α-Al2O3 introducing in-plane strain and centrosymmetry breaking. These films possess stable and programmable memristive switching behavior with a switching field of 360 V cm−1, orders of magnitude lower than in previous studies on SnS. The interplay of epitaxially induced strain and symmetry breaking in SnS is thus demonstrated, paving the way for its thin film scale integration in the next generation of energy efficient and material-level adaptive electronics.