Charge Transfer Doping of 2D PdSe<sub>2</sub> Thin Film and Its Application in Fabrication of Heterostructures
Sajeevi S. Withanage, Bhim Chamlagain, Ammon Johnston, Saiful I. Khondaker
Abstract
Abstract Palladium diselenide (PdSe 2 ) 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 PdSe 2 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 PdSe 2 thin film using benzyl viologen (BV) molecules is reported. The electrical transport measurements of the PdSe 2 device show an increase in resistance by ≈1700 percent from 2.1 MΩ for the pristine sample to 36.2 MΩ upon BV doping, revealing electrons are transferred from BV molecules to PdSe 2 resulting in an n‐doping. Raman characterization shows a red‐shift and broadening of A 3 g 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 ≈0.3 eV decrease in work function for doped PdSe 2 , consistent with the n‐doping by BV molecules. A selective doping of PdSe 2 channel is implemented for the fabrication of lateral heterojunction device which shows good current rectifying behavior with a rectification ratio of up to ≈55.