Effect of the Ultra-Thin GaN Interlayer on the Electrical and Photoelectrical Parameters of Au|GaAs Schottky Barrier Diodes

The aim of this work was to investigate the effect of the ultra-thin GaN interlayer on the electrical and photoelectrical parameters of Au|GaAs Schottky barrier diodes. An optimized fabrication process was employed to elaborate two types of Schottky diodes Au|GaAs and Au|GaN|GaAs with a GaN thickness of 2.2 nm. Electrical parameters were extracted from current–voltage measurements in dark and under illumination with a green laser of 532-nm wavelength. Surface photoelectric voltage (SPV) method was employed to estimate the excess of concentration and the mean interface state density. The extracted parameters from the current-voltage measurements in the dark, under illumination, and using SPV method show an improvement after nitridation process. The creation of the ultra-thin GaN layer at the Au|GaAs interface reduces the density of the interface states leading to the improvement of the electrical quality by restructuring the metal-semiconductor interface under the effect of formation of the GaN interfacial layer. This restructuration of the metal-semiconductor interface results in the improvement of the photoelectrical response of these structures by allowing the creation of an additional excess of concentration.