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The forward bias current-voltage (I-V) characteristics of Au/n-Si Schottky barrier diodes (SBDs) with Zn doped poly(vinyl alcohol) (PVA:Zn) interfacial layer have been investigated in the wide temperature range of 80–400 K. The conventional Richardson plot of the ln(Io/T2) versus q/kT has two linear regions: the first region (200–400 K) and the second region (80–170 K). The values of activation energy (Ea) and Richardson constant (A∗) were obtained from this plot and especially the values of A∗ are much lower than the known theoretical value for n-type Si. Also the value of Ea is almost equal to the half of the band gap energy of Si. Therefore, the Φap versus q/2kT plot was drawn to obtain the evidence of a Gaussian distribution (GD) of barrier heights (BHs) and it shows two linear region similar to ln(Io)/T2 versus q/kT plot. The analysis of I-V data based on thermionic emission of the Au/PVA:Zn/n-Si SBDs has revealed the existence of double GD with mean BH values (Φ¯B0) of 1.06 eV and 0.86 eV with standard deviation (σ) of 0.110 eV and 0.087 V, respectively. Thus, we modified ln(Io/T2)−(qσ)2/2(kT)2 versus q/kT plot for two temperature regions (200–400 K and 80–170 K) and it gives renewed mean BHs Φ¯B0 values as 1.06 eV and 0.85 eV with Richardson constant (A∗) values 121 A/cm2 K2 and 80.4 A/cm2 K2, respectively. This obtained value of A∗=121 A/cm2 K2 is very close to the known theoretical value of 120 A/cm2 K2 for n-type Si.

In this study, the forward and reverse bias current-voltage (I-V) characteristics of Au/Zinc acetate doped polyvinyl alcohol/n-Si Schottky barrier diodes (SBDs) have been investigated over the temperature range of 80-400 K. The values of zero-bias barrier height evaluated from forward and reverse bias I-V data, (ФBFo) and (ФBRo), increase with increasing temperature, and a discrepancy is observed between the values of ФBFo and ФBRo. Because the apparent barrier height (BH) seen from metal to semiconductor is higher than the one seen from semiconductor to metal, the obtained value of ФBFo is always greater than ФBRo value. The difference between them is almost the same as the Fermi energy level. The crossing of the experimental forward bias semilogarithmic ln I-V plots appears as an abnormality when compared to the conventional behavior of ideal SBDs. This behavior was attributed to the lack of free charge at a low temperature and could be expected in the temperature region where there is no carrier freezing out, which is non-negligible at low temperatures. Prior to intersection, the voltage dependent value of resistance (Ri) obtained from Ohm’s law decreases with increasing temperature, but it begins to increase after this intersection point. Such an increase in ФBo and series resistance (Rs) with temperature corresponding to high voltage region is in obvious disagreement with the reported negative temperature coefficients. However, the value of shunt resistance (Rsh) corresponding to a low or negative voltage region decreases with increasing temperature. In addition, the temperature dependent energy density distribution profiles of interface states (Nss) were obtained from forward bias I-V measurements by taking into account the bias dependence of the effective barrier height (Фe) and Rs of the device, and the values of Nss without considering Rs are almost one order of magnitude larger than Nss when considering Rs value.

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