Modulating p-type doping of two dimensional material palladium diselenide

Abstract

The van der Waals heterostructures have evolved as novel materials for complementing the Si-based semiconductor technologies. Group-10 noble metal dichalcogenides (e.g., PtS2, PtSe2, PdS2, and PdSe2) have been listed into two-dimensional (2D) materials toolkit to assemble van der Waals heterostructures. Among them, PdSe2 demonstrates advantages of high stability in air, high mobility, and wide tunable bandgap. However, the regulation of p-type doping of PdSe2 remains unsolved problem prior to fabricating p–n junction as a fundamental platform of semiconductor physics. Besides, a quantitative method for the controllable doping of PdSe2 is yet to be reported. In this study, the doping level of PdSe2 was correlated with the concentration of Lewis acids, for example, SnCl4, used for soaking. Considering the transfer characteristics, the threshold voltage (the gate voltage corresponding to the minimum drain current) increased after SnCl4 soaking treatment. PdSe2 transistors were soaked in SnCl4 solutions with five different concentrations. The threshold voltages from the as-obtained transfer curves were extracted for linear fitting to the threshold voltage versus doping concentration correlation equation. This study provides in-depth insights into the controllable p-type doping of PdSe2. It may also push forward the research of the regulation of conductivity behaviors of 2D materials.