Esaki Diode Behavior in Highly Uniform MoS2/Silicon Carbide Heterojunctions

Abstract

AbstractThe heterogeneous integration with 2D materials enables new functionalities and novel devices in state‐of‐the‐art bulk (3D) semiconductors. In this work, highly uniform MoS2 heterostructures with silicon carbide (4H‐SiC) are obtained by a facile synthesis method, highly compatible with semiconductor fab processing, i.e., the sulfurization of predeposited very‐thin (≈1.2 nm) Mo films at a temperature of 700 °C. Current–voltage characteristics of MoS2/n+‐4H‐SiC junctions collected by conductive atomic force microscopy show a pronounced negative differential resistance even at room temperature, which is a typical manifestation of band‐to‐band tunneling between degenerately p+‐/n+‐doped semiconductors. Here, the degenerate p+‐type doping of MoS2, with Nholes ≈ 4 × 1019 cm−3 evaluated by Raman mapping, is ascribed to the significant MoO3 content in the film, as demonstrated by X‐ray photoelectron spectroscopy analyses. Furthermore, atomic resolution transmission electron microscopy analyses reveal the presence of an ultrathin (≈1 nm) SiO2 tunneling barrier between MoS2 and 4H‐SiC, formed during the sulfurization process. The observation of Esaki diode behavior in MoS2 heterojunctions with 4H‐SiC opens new perspectives for this material system as a platform for ultrafast low‐power consumption digital applications.