A Comparative Study on Electrical Characteristics of Au/N-Si Schottky Diodes, with and Without Bi-Doped PVA Interfacial Layer in Dark and Under Illumination at Room Temperature

In order to see the effect of Bi-doped PVA interfacial layer on electrical characteristics, both Au/n-Si (MS) and Au/Bidoped PVA/n-Si (MPS) type Schottky barrier diodes (SBDs) were fabricated, and their main electrical parameters were investigated using current-voltage (I-V) and capacitance-voltage (C-V) measurements, in dark and under illumination at room temperature.Forward bias semi-logarithmic I-V plots of these SBDs show two distinct linear regions, with different slopes in the low and intermediate voltage region.Such behavior in I-V plots was explained by two parallel diodes model.Experimental results show that the ideality factor (n), barrier height (φ b ), series and shunt resistances (R s and R sh ), and the density of interface states/traps (N ss ) are strong functions of illumination level and applied bias voltage.The R s values were determined from the I-V characteristics, by using both Ohm's law.The energy distribution profile of N ss was also obtained from the forward bias I-V characteristics, by taking into account voltage dependent barrier height (φ e ) and ideality factor (n).It was found that Bi-doped PVA layer lead to a considerable decrease in the leakage current, R s and N ss and increase in R sh and rectifier rate (RR=I F /I R ).In conclusion, a thin Bi-doped PVA interfacial layer, considerably improved the diode performance, both in dark and under illumination.