Near-ideal van der Waals rectifiers based on all-two-dimensional Schottky junctions

Xiankun Zhang,Baishan Liu,Jiankun Xiao,Zheng Zhang,Li Gao,Yihe Liu,Zhuo Kang,Xiaozhi Liu,Qingliang Liao,Huihui Yu,Junli Du,Lin Gu,Yue Zhang

doi:10.1038/s41467-021-21861-6

Abstract

The applications of any two-dimensional (2D) semiconductor devices cannot bypass the control of metal-semiconductor interfaces, which can be severely affected by complex Fermi pinning effects and defect states. Here, we report a near-ideal rectifier in the all-2D Schottky junctions composed of the 2D metal 1 T′-MoTe2 and the semiconducting monolayer MoS2. We show that the van der Waals integration of the two 2D materials can efficiently address the severe Fermi pinning effect generated by conventional metals, leading to increased Schottky barrier height. Furthermore, by healing original atom-vacancies and reducing the intrinsic defect doping in MoS2, the Schottky barrier width can be effectively enlarged by 59%. The 1 T′-MoTe2/healed-MoS2 rectifier exhibits a near-unity ideality factor of ~1.6, a rectifying ratio of >5 × 105, and high external quantum efficiency exceeding 20%. Finally, we generalize the barrier optimization strategy to other Schottky junctions, defining an alternative solution to enhance the performance of 2D-material-based electronic devices.

Highlights

The applications of any two-dimensional (2D) semiconductor devices cannot bypass the control of metal-semiconductor interfaces, which can be severely affected by complex Fermi pinning effects and defect states
The detailed differences between the general and optimized Schottky junctions by the conventional and 2D metals are summarized in Fig. 1a, b
A near-ideal 1T′-MoTe2/MoS2 Schottky diode with a large Schottky barrier height was successfully fabricated by stacking the 2D metallic 1T′-MoTe2 and the semiconducting monolayer MoS2

Summary

Introduction

The applications of any two-dimensional (2D) semiconductor devices cannot bypass the control of metal-semiconductor interfaces, which can be severely affected by complex Fermi pinning effects and defect states. The traditional merits of Schottky diodes are not reproduced in 2D material-based Schottky diodes but are replaced by many deficiencies, such as excessive reverse leakage current (i.e., large power consumption), low current rectifying ratio, and poor ideality factor[4,11,12,13,14,15]. This is attributed to the composition effect of the low Schottky barrier height and the tiny. Lattice defect healing is an optimal strategy to efficiently and stably decrease the intrinsic defect doping of ultrathin 2D materials[28,29]

Methods

Results

Conclusion