Enhancement of Photovoltaic Response in Multilayer MoS₂ Induced by Plasma Doping

TLDR

Layered transition‑metal dichalcogenides promise ultrathin photovoltaic devices with excellent performance, flexibility, long lifetime, and low cost, but engineering their band structures is essential. We present a plasma‑assisted doping approach to significantly improve the photovoltaic response in multilayer MoS₂ and provide insights for leveraging 2D materials in optoelectronics. The authors fabricated vertically stacked ITO/MoS₂/metal photovoltaic devices and applied plasma‑assisted p‑doping to create p–n junctions. Plasma‑induced p‑doping forms p–n junctions that enhance photovoltage, reduce reverse dark current, and yield short‑circuit photocurrent densities up to 20.9 mA cm⁻² and power‑conversion efficiencies up to 2.8 % under AM1.5G illumination, with high external quantum efficiencies.

Abstract

Layered transition-metal dichalcogenides hold promise for making ultrathin-film photovoltaic devices with a combination of excellent photovoltaic performance, superior flexibility, long lifetime, and low manufacturing cost. Engineering the proper band structures of such layered materials is essential to realize such potential. Here, we present a plasma-assisted doping approach for significantly improving the photovoltaic response in multilayer MoS2. In this work, we fabricated and characterized photovoltaic devices with a vertically stacked indium tin oxide electrode/multilayer MoS2/metal electrode structure. Utilizing a plasma-induced p-doping approach, we are able to form p–n junctions in MoS2 layers that facilitate the collection of photogenerated carriers, enhance the photovoltages, and decrease reverse dark currents. Using plasma-assisted doping processes, we have demonstrated MoS2-based photovoltaic devices exhibiting very high short-circuit photocurrent density values up to 20.9 mA/cm2 and reasonably good power-conversion efficiencies up to 2.8% under AM1.5G illumination, as well as high external quantum efficiencies. We believe that this work provides important scientific insights for leveraging the optoelectronic properties of emerging atomically layered two-dimensional materials for photovoltaic and other optoelectronic applications.