Physical properties enhancement of porous silicon treated with In2O3 as a antireflective coating

Abstract

In this work, we investigate the effect of Indium Oxide (In2O3) on the microstructural, optical, optoelectrical, and electrical properties of Porous Silicon (PS) layer. PS film was prepared by electrochemical anodization technique. In2O3 thin film was coated onto PS layer by using simple chemical immersion method. The investigation showed a significant enhancement in the optoelectronic property of PS coated with In2O3. The In2O3/PS layer was thermally annealed to improve the efficiency of the photovoltaic cells. Surface morphology and chemical composition modification of In2O3/PS were analyzed by atomic force microscopy (AFM) and Fourier transfer infrared (FTIR) spectroscopy. Optical reflectivity of sample In2O3/PS decreases significantly from 30% to 2.4% owing to an improvement in the light absorption. The optical parameters such as refractive index (n) and extinction coefficient (k), real and imaginary dielectric constants (ε1 & ε2), as well as the components percentage and thickness of samples were determined by analyzing the TanΨ and CosΔ ellipsometric parameters. Photoluminescence (PL) analysis of PS layer treated with In2O3 before and after annealing indicated a bleu emission shifts due to the quantum confinement effect of the oxidized silicon nanocrystals. Annealed PS coated In2O3 resulted a significant improvement in the minority carrier lifetime (τeff) from 2 to 16.4 μs. The optoelectronic and electronic quality of the treated PS layer with In2O3 was enhanced noticeably compared to the untreated porous layer, making it an ideal candidate for the solar cell applications. Keywords: Porous silicon, Indium oxide, Reflectivity, Photoluminescence, Spectroscopic ellipsometry, Lifetime