Growth of MoS2-Nb-doped MoS2 lateral homojunctions: A monolayer p-n diode by substitutional doping

Monolayer transition metal dichalcogenides (TMDs) have been considered as promising materials for various next-generation semiconductor devices. However, carrier doping techniques for TMDs, which are important for device fabrication, have not been completely established yet. Here, we report a monolayer p-n junction formed using in situ substitutional doping during chemical vapor deposition (CVD). We synthesized monolayer MoS2-Nb-doped MoS2 lateral homojunctions using CVD and then characterized their physical and electrical properties. The optimized growth condition enabled us to obtain spatially selective and heavy Nb doping in the edge region of a single-crystalline MoS2, thus resulting in an obvious work function difference between the inner and edge regions of the crystal. The obtained monolayer crystal demonstrated n-type and degenerate p-type semiconducting behaviors in each region, and a clear rectifying behavior across the n-type and p-type interface was observed. We believe that the results obtained can expand the research field of exploring two-dimensional homo p-n junctions, which can be important for realizing various TMD-based devices, such as diodes and field-effect transistors, with low-contact resistance.(c) 2021 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license(http://creativecommons.org/licenses/by/4.0/).

Automated summary

This study reports the formation of a monolayer p-n junction in MoS2 using chemical vapor deposition. By optimizing the growth conditions, spatially selective and heavy Nb doping was successfully achieved, resulting in a significant work function difference between the inner and edge regions of the single-crystalline MoS2, leading to n-type and degenerate p-type semiconductor behaviors along with clear rectifying behavior.