Investigation of electrical properties of metal-polymer-semiconductor (MPS) structures depending on frequency and voltage

This comprehensive study presents an in-depth exploration of modified gold (Au) on silicon (n-Si) diodes. The modification was performed by applying a Polyvinyl Alcohol (PVA) interfacial layer onto the n-Si wafer using the spin coating method, thereby creating an Au/PVA/n-Si diode with a Metal-Polymer-Semiconductor (MPS) structure. The properties and characteristics of these diodes were investigated and evaluated under room temperature conditions at two frequencies, 5kHz and 5MHz. The study systematically addressed the analysis of the direct and reverse bias current-voltage (I-V), capacitance-voltage (C-V), and conductance-voltage (G/ω-V) characteristics of the modified diodes. Key electrical parameters such as the ideality factor (n), series resistance (Rs), shunt resistance (Rsh), and barrier height (ΦB) were obtained from these bias voltage I-V characteristics, providing critical insight into the functioning and performance of the modified diodes. A variety of methods were employed for the computation of these parameters, including Cheung functions, Ohm's law, and Norde's method. The calculated series resistance (Rs) values were obtained from these methods and their implications were duly examined. Further examination was conducted on the admittance, C-V and G/ω-V characteristics of the modified Au/PVA/n-Si diode. This was done under two sets of conditions - dark and illuminated. The primary electrical parameters including the thickness of the depletion layer width (WD) and the barrier height (ΦB(C-V)) were determined from the reverse bias C-2-V curves for both sets of conditions. In an enlightening revelation, the study found a strong correlation between the illumination conditions and the voltage-dependent Rs values. These were obtained using C-V and G/ω-V data under both dark and 100 mW/cm2 illumination conditions. This study firmly establishes that the I-V, C-V, and G/ω-V characteristics of the Au/PVA/n-Si diode are heavily influenced by illumination. The evidence from this research provides a substantial understanding of the behavior of MPS structures. This is not only significant from an academic perspective but is also set to influence real-world applications. It unlocks new possibilities for the wider application of these structures in the fields of electronics and optics, giving researchers, engineers, and technologists an enriched perspective and a practical edge.