Perpendicular sheet-like alignment of a self-driven MoS₂/Si heterostructure for Vis-NIR wavelength detection

In this article, a self-powered heterostructure based on perpendicularly aligned n-MoS₂/p-Si was fabricated for Vis-NIR wavelength detection. In particular, MoS₂ sheet-like morphology was attained via hydrothermal treatment at two crystallization temperatures (180 °C and 240 °C). The average thicknesses of the sheet-like structures were 85 and 45 nm for samples treated at 180 °C and 240 °C, respectively. The proposed geometry exhibited rectifying behavior, with the I_ph/I_D ratio reaching the order of ∼10³ at zero applied bias, indicating the self-powered nature of the demonstrated MoS₂/Si heterostructure; this was attained along with an R² value close to unity as a function of the applied light intensity variation. Photoresponsivity (R_λ) exhibited wide reaching performance (Vis-NIR) with a peak value of 0.36 mA W^-1 at 625 nm and 6 mW cm^-2, this was acquired at zero applied bias. R_λ demonstrated a descending profile as the intensity of incident light increased to 17 mW cm^-2 (0.19 mA W^-1). The response and recovery time of the fabricated devices (180 °C and 240 °C) exhibited rather fast episodes with values of 0.178/0.181 and 0.176/0.185 s, respectively, which in turn indicated faster electron injection than recombination.