Ultraviolet laser-induced depolymerization of polyvinylpyrrolidone for decreasing off-current of 2D tellurium transistors

Abstract

Tellurium (Te) is an emerging two-dimensional (2D) p-type material with remarkable air stability and exceptionally high p-channel mobility, making it ideal for next-generation electronics. For the synthesis of Te, the hydrothermal method using polyvinylpyrrolidone (PVP) as a capping ligand is commonly employed because of the challenges associated with the mechanical exfoliation of Te. However, the residual PVP after thinning and cleaning hinders the expression of the intrinsic optical and electrical properties of 2D Te, thereby limiting its overall performance. In this study, we present an ultraviolet laser-assisted PVP removal method, validated by photoluminescence and Raman spectroscopy, which effectively eliminates PVP residues while preserving the integrity of the host material. Furthermore, the removal of organic cross-links was confirmed by additional photooxidation peaks in X-ray photoelectron spectra. The proposed method resulted in a tenfold reduction in the off-current in 2D Te-based field-effect transistors, demonstrating its effectiveness. This study demonstrates significant advancements in solution-processed 2D materials and provides a versatile approach for ligand-assisted synthesis and device applications.