Light induced enhancement of minority carrier lifetime of chemically passivated crystalline silicon

Abstract

In this work we present light effects on chemically passivated silicon surface. Di-iodine–ethanol (I–E) mixtures were used to passivate silicon dangling bonds. The passivation quality is sensitive to both silicon surface state and light irradiation. The minority carrier lifetime values vary from 2μs for unpassivated surfaces to about 40μs for chemically passivated ones. FTIR investigations show that light irradiation catalyses the passivation effect by forming the silicon-ethoxylate group (SiOC2H5). We suggest a mechanism to explain the passivation effect based on carrier-induced dissociation of I2.