Series resistance and interface states effects on the C-V and G/w-V characteristics in Au/(Co_3O_4-doped PVA)-Si structures at room temperature

摘要

Microwave-assisted method has been used for preparation of Co_3O_4 nanopowders. Then, Co_3O_4-doped polyvinyl alcohol (PVA) composites are deposited on n-Si wafer using spin coating method. The main electrical parameters of the Au/(Co_3O_4-doped PVA)-Si type Schotkky barrier diodes (SBDs) have been investigated by capacitance-voltage-frequency (C-V-f) and conductance-voltage-frequency (G/ω-V-f) measurements at room temperature and they were performed in the frequency range of 2 kHz-2 MHz and at (±4.5 V) by 50 mV steps. The XRD pattern of the as-prepared sample show that all diffraction peaks appeared in this pattern match very well with ICDD data and they can be readily indexed to the Co_3O_4 nanostructures, no other peaks were observed, which indicates the high purity of the sample. The effects of (Co_3O_4-doped PVA), series resistance (Rs) and surface states (Nss) on electrical characteristics have been investigated in detail. In order to eliminate the effect of Rs on high frequencies these measurements, the measured Cm and Gm/ω values were adjustment. The high values of Nss at low frequencies are responsible for the non-ideal behavior of C-V and G/ω-V characteristics. The obtained value of N_D exponentially decreases; the value of Φ_B (C-V) exponentially increases with increases frequency. Such behavior of N_D and Φ_B (C-V) are expected behavior and it is attributed to the particular density distribution of N_(ss), polarization processes and interfacial layer. Experimental results show that the C-V and G/ω-V characteristics of SBDs are affected not only in Nss and Rs but also interfacial polymer (Co_3O_4-doped PVA) layer.