Negative series resistance and photo-response properties of Au/PPY-MWCNTs composite/TiO2/Al2O3/n-Si/Al photodiode

Abstract The paper addresses a novel approach concerning the appearance of negative series resistance (Rs) at high frequencies for both temperatures and voltages. Most of the previous studies have focused on the relationship between voltage and current (I - V) to determine the value of Rs using several methods. By measuring capacitance and conductance as a function of voltage, we were able to develop a systematic analysis of series resistance. At high frequencies of 2 × 107, 107 Hz, Rs has negative values however, at frequency 106 Hz it takes both positive and negative values, whilst from (105 − 10) Hz it has positive values. Here in this article, we synthesized Au/PPY-MWCNTs/TiO2/Al2O3/n-Si/Al structure which can be used in a variety of applications such as supercapacitors, and diodes. We investigated the electrical properties such as ideality factor (n), barrier height (фb), series resistance using several approaches such as conventional, Chueng, and Nord methods. The structure has shown rectification with a good response to daylight illumination. The structure response to daylight illumination indicates that photodiodes have the potential to be used as solar detectors.