Visible to near-infrared photodetectors based on MoS₂ vertical Schottky junctions

Over the past few years, two-dimensional (2D) nanomaterials, such as MoS₂, have been widely considered as the promising channel materials for next-generation high-performance phototransistors. However, their device performances still mostly suffer from slow photoresponse (e.g. with the time constant in the order of milliseconds) due to the relatively long channel length and the substantial surface defect induced carrier trapping, as well as the insufficient detectivity owing to the relatively large dark current. In this work, a simple multilayer MoS₂ based photodetector employing vertical Schottky junctions of Au-MoS₂-ITO is demonstrated. This unique device structure can significantly suppress the dark current down to 10^-12 A and enable the fast photoresponse of 64 μs, together with the stable responsivity of ∼1 A W^-1 and the high photocurrent to dark current ratio of ∼10⁶ at room temperature. This vertical-Schottky photodetector can also exhibit a wide detection range from visible to 1000 nm. All these results demonstrate clearly that the vertical Schottky structure is an effective configuration for achieving high-performance optoelectronic devices based on 2D materials.