Effect of series resistance and interface states on the I–V, C–V and G/ω–V characteristics in Au/Bi-doped polyvinyl alcohol (PVA)/n-Si Schottky barrier diodes at room temperature

The forward and reverse bias current–voltage (I–V), capacitance–voltage (C–V) and conductance–voltage (G/ω–V) characteristics of the Au/PVA (Bi-doped)/n-Si Schottky barrier diodes (SBDs) have been investigated at room temperature by taking the interface states (Nss) and series resistance (Rs) effects into account. The voltage dependent profiles of resistance (Ri) were obtained from both the I–V and C/G–V measurements by using Ohm’s Law and Nicollian methods. The obtained values of Ri with agreement each other especially at sufficiently high bias voltages which correspond the value of Rs of the diode. Therefore, the energy density distribution profile of Nss was obtained from the forward bias I–V data taking the bias dependence of the effective barrier height (BH) Φe and Rs into account. The high value of ideality factor (n) was attributed to high density of Nss and interfacial polymer layer at metal/semiconductor (M/S) interface. In order to examine the frequency dependence of some of the electrical parameters such as doping donor concentration (ND), Φe, Rs and Nss values, C–V and G/ω–V measurements of the diode were performed at room temperature in the frequency range of 50 kHz–5 MHz. Experimental results confirmed that the Nss, Rs and interfacial layer are important parameters that influence electrical characteristics of SBD.