Demonstration of the Formation of Porous Silicon Films with Superior Properties Formed on Polished (100) Si with Screen-Printed Back Contacts

Abstract

Porous silicon (PS) layers were formed by anodization on polished substrates of (1 0 0) Si at different current densities for a fixed anodization time of 30 mins. using different screenprinted/ evaporated back contacts (Ag, Al) respectively. The PS films has been characterized by high resolution X-ray diffraction (HRXRD), photoluminescence (PL), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) techniques respectively. Porosity and thickness of PS layers were estimated by gravimetric analysis. The properties of PS formed using screen-printed Ag & Al as the back contacts (SP-(Ag/Al)) was found to be superior as compared to the corresponding films with evaporated back contacts (EV-(Ag/Al)). The PS formed with screenprinted Ag & Al-back contacts shows better crystalline perfection, higher stability, higher PL efficiency and negligible PL decay compared to that formed with evaporated Ag & Al- as the back contact for the same current density and time of anodization.