Reduced Reverse Leakage in Ti/PtSe2/n-GaN Schottky Diodes Enabled by an Ultrathin PtSe2 Interlayer

Gallium nitride (GaN) Schottky barrier diodes (SBDs) are promising for power electronics, but their reverse-bias leakage remains strongly influenced by the rectifying interface’s microscopic nature. We fabricated PtSe2/n-GaN diodes with a transferred ultrathin PtSe2 interlayer (∼1.56 nm, trilayer) to weaken direct interfacial chemical bonding. The Ti/PtSe2/n-GaN devices exhibit a suppressed reverse leakage current density of 1.3×10−7A/cm2 at −1 V, a 7.5×104 rectification ratio at ±1 V, a 0.8 V turn-on voltage, and a 144 V breakdown voltage. Same-wafer Ti/n-GaN control devices display much higher leakage (6.23×10−5A/cm2 at −1 V) and a lower rectification ratio (1.144×103). Furthermore, Pt/PtSe2/n-GaN devices reduce leakage to 1.19×10−8A/cm2 and increase the rectification ratio to 1.09×105. These results demonstrate the ultrathin interlayer effectively suppresses reverse leakage while preserving the rectifying interface’s sensitivity to anode metal selection.