Charge Transfer Doping of 2D PdSe2 Thin Film and Its Application in Fabrication of Heterostructures

Palladium diselenide (PdSe2) is an emerging 2D material with exotic optical and electrical properties and widely tunable layer dependent band gap in the infrared regime. The ability to further tune the electronic properties of PdSe2 via doping is of fundamental importance for a wide range of electronic and optoelectronic device applications. Here, surface charge transfer doping of chemical vapor deposition grown p-type PdSe2 thin film using benzyl viologen (BV) molecules is reported. The electrical transport measurements of the PdSe2 device show an increase in resistance by approximate to 1700 percent from 2.1 M omega for the pristine sample to 36.2 M omega upon BV doping, revealing electrons are transferred from BV molecules to PdSe2 resulting in an n-doping. Raman characterization shows a red-shift and broadening of A(g)(3) characteristic peak for the doped sample, while X-ray photoelectron spectroscopy shows a negative shift in Pd 3d and Se 3d binding energies confirming n-doping by BV. Kelvin force probe microscopy measurements show a approximate to 0.3 eV decrease in work function for doped PdSe2, consistent with the n-doping by BV molecules. A selective doping of PdSe2 channel is implemented for the fabrication of lateral heterojunction device which shows good current rectifying behavior with a rectification ratio of up to approximate to 55.

Automated summary

Palladium diselenide (PdSe2) is a 2D material with exotic properties that can be further manipulated through surface charge transfer doping with benzyl viologen (BV) molecules to achieve n-doping, leading to the fabrication of lateral heterojunction devices with good current rectifying behavior.