Black Phosphorus-Monolayer MoS2 van der Waals Heterojunction P-N Diode

TL;DR

This paper reports the creation of a gate-tunable black phosphorus/MoS2 heterojunction p-n diode that exhibits high photodetection responsivity and photovoltaic energy conversion, advancing 2D material-based optoelectronic devices.

Contribution

It demonstrates the first black phosphorus/monolayer MoS2 heterojunction p-n diode with tunable electrical and optoelectronic properties.

Findings

Maximum responsivity of 418 mA/W at 633 nm

Photovoltaic energy conversion with 0.3% external quantum efficiency

Potential for broadband photodetection and solar energy harvesting

Abstract

Phosphorene, an elemental 2D material, which is the monolayer of black phosphorus, has been mechanically exfoliated recently. In its bulk form, black phosphorus shows high carrier mobility (~10000 cm2/Vs) and a ~0.3 eV direct bandgap. Well-behaved p-type field-effect transistors with mobilities of up to 1000 cm2/Vs, as well as phototransistors, have been demonstrated on few-layer black phosphorus, showing its promise for electronics and optoelectronics applications due to its high hole mobility and thickness-dependence direct bandgap. However, p-n junctions, the basic building blocks of modern electronic and optoelectronic devices, have not yet been realized based on black phosphorus. In this paper, we demonstrate a gate tunable p-n diode based on a p-type black phosphorus/n-type monolayer MoS2 van der Waals p-n heterojunction. Upon illumination, these ultra-thin p-n diodes show a maximum photodetection responsivity of 418 mA/W at the wavelength of 633 nm, and photovoltaic energy conversion with an external quantum efficiency of 0.3%. These p-n diodes show promise for broadband photodetection and solar energy harvesting.