Improved barrier homogeneity in Pt/Al0.75Ga0.25N Schottky barrier diodes by graphene interlayer

Abstract Pt/Al 0.75 Ga 0.25 N Schottky barrier diodes (SBDs) with graphene (w/Gr) and without graphene (w/o Gr) interlayer between metal and semiconductor were fabricated to determine the effects of Gr interlayer on the device electrical characteristics. The temperature dependent current–voltage ( I–V ) and capacitance–voltage ( C–V ) characteristics were systematically measured and comparably analyzed for both structures. The ideality factor (n) and Schottky barrier height (SBH) were determined by the thermionic emission model and barrier inhomogeneity model. The results reveal that the values of ideality factor varied from 4.25 to 2.5 for w/Gr SBDs and 6.61 to 3.19 for w/o Gr SBDs with a temperature range from 293 to 433 K. The mean barrier height and standard deviation values are 2.355 and 0.266 eV for w/Gr SBDs, while 2.128 and 0.272 eV for w/o Gr SBDs, respectively. The C–V data also shows the enhancement of the SBH for w/Gr SBDs. The results indicate a higher SBH and more barrier uniform distribution for w/Gr SBDs compared to w/o Gr SBDs, contributing to a quality improvement of Schottky contact. The insights granted by this research may pave a new pathway for improving the performance of AlGaN SBDs through Gr engineering.