Tunable Electron Transport in Defect-Engineered PdSe₂

Tuning the ambipolar behavior in charge carrier transportvia defect-engineeringis crucial for achieving high mobility transistors for nonlinear logiccircuits. Here, we present the electric-field tunable electron andhole transport in a microchannel device consisting of highly air-stablevan der Waals (vdW) noble metal dichalcogenide (NMDC), PdSe2, as an active layer. Pristine bulk PdSe2 constitutesSe surface vacancy defects created during the growth or exfoliationprocess and offers ambipolar transfer characteristics with a slightelectron dominance recorded in field-effect transistor (FET) characteristicsshowing an ON/OFF ratio <10 and electron mobility & SIM;21 cm(2)/(V & BULL;s). However, transfer characteristics of PdSe2 can be tuned to a hole-dominated transport while using hydrochloricacid (HCl) as a p-type dopant. On the other hand,the chelating agent EDTA, being a strong electron donor, enhancesthe electron-dominance in PdSe2 channel. In addition, p-type behavior with a 100 times higher ON/OFF ratio isobtained while cooling the sample down to 10 K. Low-temperature angle-resolvedphotoemission spectroscopy resembles the p-type bandstructure of PdSe2 single crystal. Also, first principledensity functional theory calculations justify the tunability observedin PdSe2 as a result of defect-engineering. Such a defect-sensitiveambipolar vdW architecture may open up new possibilities toward futureCMOS (Complementary Metal-Oxide-Semiconductor) device fabricationsand high performance integrated circuits.