Molecular Precursor-Directed Growth of Nanostructured SnS2 for Memristive and Neuromorphic Electronics

Abstract

Low-dimensional layered metal chalcogenides have recently garnered significant attention for advanced electronic and optoelectronic applications, particularly memristive and synaptic devices; however, achieving purity and scalable fabrication remains a key challenge. We demonstrate a facile and scalable in-situ solvothermal approach enabling low-temperature deposition of SnS₂ thin films, employing the single-source precursor (SSP) [Cl2Sn(S2P(OiC3H7)2)2]. The distorted octahedral complex [Cl2Sn(S2P(OiC3H7)2)2], synthesized from SnCl4 and characterized by multinuclear NMR (1H, 31P{¹H}, 119Sn{1H}) and IR spectroscopy, acts as an efficient SSP for solvothermal deposition of SnS2 on ITO substrates. X-ray diffraction confirmed the formation of pure, single-phase, crystalline hexagonal SnS2, while the composition and morphology were corroborated by SEM, EDX, Raman, and XPS analyses. UV–vis spectroscopy further revealed an optical bandgap of 2.06 eV. Leveraging this synthesis route, Ag/SnS2/ITO memristive device was fabricated, exhibiting electroforming-free bipolar resistive switching at ±0.6 V. The device demonstrated stable endurance over more than 102 cycles with an ON/OFF ratio of ~10. Additionally, the device further exhibits analogue conductance modulation and synaptic plasticity, enabling emulation of biological learning behaviour when implemented in a hardware-aware artificial neural network. The experimentally derived weight update dynamics achieved 92% classification accuracy on the MNIST dataset. Collectively, these findings establish SSP-derived SnS2 thin films as a viable material platform for emerging memory and neuromorphic electronics.