Characteristics of interface states in irradiated Pd/n-SiGe as derived from frequency- and temperature-dependent admittance

We have used, in this contribution, the measured frequency-dependent ac admittance of irradiated Pd/n-GaN Schottky contacts at different temperatures ranging from 100K to 300K to derive the admittance associated with the displacement current in the Pd/GaN interfacial layer. The normalized conductance versus frequency plots at various temperatures, are characterized essentially by the presence of peaks, which is seen as a signature and a direct evidence for the presence of interface traps. The magnitudes and frequency positions of these peaks allowed the determination of the density and the energy distribution of interface traps as well as the thermal emission rates of carriers from traps and, hence, their capture cross-section.