Large-Scale Conformal Growth of Atomic-Thick MoS2 for Highly Efficient Photocurrent Generation

TL;DR

This paper demonstrates a controllable method for large-scale conformal growth of monolayer MoS2 on textured substrates, achieving record-high photocurrent responsivity suitable for optoelectronic devices.

Contribution

It introduces a novel chemical vapor deposition technique enabling uniform monolayer MoS2 on rugged surfaces with significantly enhanced photo-responsivity.

Findings

Photocurrent responsivity of ~254.5 mA/W on nano-rugged substrates

59 times higher responsivity compared to planar MoS2

Record high photocurrent generation under low bias

Abstract

Controlling the interconnection of neighboring seeds (nanoflakes) to full coverage of the textured substrate is the main challenge for the large-scale conformal growth of atomic-thick transition metal dichalcogenides by chemical vapor deposition. Herein, we report on a controllable method for the conformal growth of monolayer MoS2 on not only planar but also micro- and nano-rugged SiO2/Si substrates via metal-organic chemical vapor deposition. The continuity of monolayer MoS2 on the rugged surface is evidenced by scanning electron microscopy, cross-section high-resolution transmission electron microscopy, photoluminescence (PL) mapping, and Raman mapping. Interestingly, the photo-responsivity (~254.5 mA/W) of as-grown MoS2 on the nano-rugged substrate exhibits 59 times higher than that of the planar sample (4.3 mA/W) under a small applied bias of 0.1 V. This value is record high when compared with all previous MoS2-based photocurrent generation under low or zero bias. Such a large enhancement in the photo-responsivity arises from a large active area for light-matter interaction and local strain for PL quenching, where the latter effect is the key factor and unique in the conformally grown monolayer on the nano-rugged surface. The result is a step toward the batch fabrication of modern atomic-thick optoelectronic devices.