Epitaxial Growth of Step-Like Cr2 S3 Lateral Homojunctions Towards Versatile Conduction Polarities and Enhanced Transistor Performances

Small. 2022 Jan;18(4):e2105744. doi: 10.1002/smll.202105744. Epub 2021 Nov 27.

Abstract

For expanding the applications of 2D transition metal dichalcogenides (TMDCs), integrating functional devices with diverse conduction polarities in the same parent material is a very promising direction. Improving the contact issue at the metal-semiconductor interface also holds fundamental significance. To achieve these concurrently, step-like Cr2 S3 vertical stacks with varied thicknesses are achieved via a one-step chemical vapor deposition (CVD) method route. Various types of 2D Cr2 S3 lateral homojunctions are thus naturally evolved, that is, pm -ambipolar/n, p/ambipolar, ambipolar/n, and nm -ambipolar/n junctions, allowing the integration of diverse conduction polarities in single Cr2 S3 homojunctions. Significantly, on-state current density and field-effect mobility of the thinner 2D Cr2 S3 flakes stacked below are detected to be ≈5 and ≈6 times increased in the lateral homojunctions, respectively. This work should hereby provide insights for designing 2D functional devices with simpler structures, for example, multipolar field-effect transistors, photodetectors, and inverters, and provide fundamental references for optimizing the electrical performances of 2D materials related devices.

Keywords: Cr 2S3; conduction polarity; epitaxial growth; lateral homojunctions.