A thousand-fold enhancement of photoluminescence in porous silicon using ion irradiation

Abstract

A large increase in the porosity of highly doped p-type silicon is observed at the end-of-range depth of high-energy ions after subsequent electrochemical anodization. This occurs under certain conditions of irradiation geometry and fluence, owing to the dual effects of increased wafer resistivity and a locally increased current density during anodization. This results in the creation of highly porous, sub-surface zones which emit photoluminescence with an intensity of more than three orders of magnitude greater than the surrounding mesoporous silicon, comparable to that produced by microporous silicon. This provides means of selectively enhancing and patterning the photoluminescence emission from micron-sized areas of porous silicon over a wide range of intensity. © 2013 AIP Publishing LLC.