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

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 2 μs for unpassivated surfaces to about 40 μs for chemically passivated ones. FTIR investigations show that light irradiation catalyses the passivation effect by forming the silicon-ethoxylate group (single bondSisingle bondOsingle bondC2H5). We suggest a mechanism to explain the passivation effect based on carrier-induced dissociation of I2.