Structural, morphological and optoelectronic properties of porous silicon combined alumina coating film deposited by PLD

摘要

Pulsed laser deposition of Al_2O_3 onto porous silicon (PS) is shown to provide excellent passivation of multi-crystalline silicon surfaces intended for solar cells applications. Surface passivation and reflectivity are investigated before and after the deposition of various nominal thicknesses of Al_2O_3 ranging from isolated nanoparticles to ~80 nm-thick films. The level of surface passivation is determined by techniques based on photoconductance and FTIR. As a result, the effective minority carrier lifetime increase from 1 to 130 μs at a minority carrier density (Δn) of 1 × 10~(13) cm~(−3). However, passivation scheme provide a significant decrease in the reflectivity; it’s reduced from 28% to about 5% after Al_2O_3/PS coating.