Hybrid, Gate-Tunable, van der Waals p-n Heterojunctions from Pentacene and MoS2

TL;DR

This paper demonstrates a novel hybrid p-n heterojunction device combining organic pentacene with 2D MoS2, showing gate-tunability, asymmetric transfer characteristics, and photovoltaic effects, expanding the scope of van der Waals heterostructures.

Contribution

It introduces a new hybrid organic-2D heterojunction with tunable electronic properties and photovoltaic behavior, broadening the application of van der Waals heterostructures beyond layered solids.

Findings

Gate-tunable p-n heterojunction with asymmetric control

Observation of photovoltaic effect due to type II band alignment

Potential for hybrid solar cell applications

Abstract

The recent emergence of a wide variety of two-dimensional (2D) materials has created new opportunities for device concepts and applications. In particular, the availability of semiconducting transition metal dichalcogenides, in addition to semi-metallic graphene and insulating boron nitride, has enabled the fabrication of all 2D van der Waals heterostructure devices. Furthermore, the concept of van der Waals heterostructures has the potential to be significantly broadened beyond layered solids. For example, molecular and polymeric organic solids, whose surface atoms possess saturated bonds, are also known to interact via van der Waals forces and thus offer an alternative for scalable integration with 2D materials. Here, we demonstrate the integration of an organic small molecule p-type semiconductor, pentacene, with a 2D n-type semiconductor, MoS2. The resulting p-n heterojunction is gate-tunable and shows asymmetric control over the anti-ambipolar transfer characteristic. In addition, the pentacene-MoS2 heterojunction exhibits a photovoltaic effect attributable to type II band alignment, which suggests that MoS2 can function as an acceptor in hybrid solar cells.