Electrical Properties and Conduction Mechanism of Au/C20H12/n-Si Structure at High Temperatures Utilizing Impedance Measurements

The temperature-dependent changes in the capacitance–voltage (C–V) and conductivity–voltage (G/w–V) curves of the Au/C20H12/n-Si structure were investigated in the high-temperature range of 280–400 K. C and G values were strongly dependent on both temperature and bias voltage, especially in the depletion and accumulation regions in the experimental results. Basic electrical parameters including dopant donor atoms (ND), depletion layer thickness (Wd), barrier height (ФB), series resistance (Rs), and Fermi energy level (EF) were calculated from the reverse bias (1/C2–V) characteristic for each temperature. Among the parameters that have a significant effect on the performance of these devices, the voltage-dependent resistance profile (Ri) was obtained using the Nicollian-Brews technique, and the surface states (Nss) were obtained using the Hill-Coleman technique. While ND increases with increasing temperature, Rs, Nss, and ФB decrease. The observed abnormal/anomalous peak in both the C–V and Rs–V plots and shifting of its positions and magnitude were attributed to a special distribution of Nss in the semiconductor bandgap and their reordering/restriction under temperature and electric field effects. Both the C–V and G/w–V curves of the structure at room temperature were corrected considering the Rs effect to obtain the real C and G/w values.