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 (R _s ) 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 R _s 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 × 10 ^7 , 10 ^7 Hz, R _s has negative values however, at frequency 10 ^6 Hz it takes both positive and negative values, whilst from (10 ^5 − 10) Hz it has positive values. Here in this article, we synthesized Au/PPY-MWCNTs/TiO _2 /Al _2 O _3 /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 (ф _b ), 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.

Keywords

• multiwalled carbon nanotube (mwcnt)—polypyrrole (ppy)- polymer oxide semiconductor (pos)- heterojunction diode—c-v characterization- series resistance (rs)