Porous silicon layers prepared by electrochemical etching for application in silicon thin film solar cells

In this paper, multilayer structures of porous silicon were fabricated by using electrochemical etching and characterized for its optical properties and surface morphology. Samples of monolayer of porous silicon were grown to study the characteristics of porous layer formation with respect to applied current density, etching time and hydrofluoric acid concentrations. Photoluminescence peaks of red emission at wavelength 695 and 650 nm were observed from multilayer porous silicon structures. By atomic force microscopy measurement, hillocks like surface were clearly observed within the host material, which confirmed the formation of pores.

► Optical & structural properties of multilayer porous silicon are studied.
► Desired refractive index and thickness profile of porous silicon layers can be attained.
► Multilayer structure of porous silicon is useful as a bottom layer for solar cells.
► Recombination of electrons and holes can be prevented for a longer time by trapping the photons.
► This analysis is useful to yield high conversion efficiency of new generation PV cells.