Effective suppression of nano-textured black silicon surface recombination channels through sputtered aluminum oxide: A comparison study with ALD grown films.

Abstract

This accepted manuscript was withdrawn on 2 November 2020 on the author's request.In this work, the effective surface passivation of nano-textured silicon (NT-Si) using sputtered aluminum oxide (AlOx) films has been demonstrated and established a comparison with atomic layer deposition (ALD) grown AlOx films. Silver assisted wet chemical etching (SAWCE) is used to prepare optically black NT-Si. Sub-wavelength size features of NT-Si surface optimized to control the surface defect states which act as trap centres for charge carriers and proportional to the surface area. Sputtered and ALD grown AlOx films used to passivate the NT-Si surfaces are analyzed primarily in context of available trap centres. The AlOx/NT-Si interface is quantified by the density of interface trap states (Dit) and the total fixed charge (Qf) that correlated with effective surface recombination velocity (Seff) of carriers. The estimated Dit and Qf of sputtered AlOx films are ~4 x 1011 eV-1cm-2 and ~7 x 1012 cm-2, respectively which results in the Seff of ~37 cm/s due to the field-effect passivation. While the Dit and Qf of ALD grown AlOx films are 1.1 x 1011 eV-1cm-2 and ~7.8 x 1012 cm-2 results in the Seff of ~22 cm/s owing to both the chemical and field-effect passivation.