Anti-reflection glass coverslips for indoor MOS photovoltaic cells

Abstract

This article discusses the use of glass coverslips with thickness in the range of 70 to 108 µm as anti-reflection layers in order to increase the efficiency of MOS photovoltaic cells with Al/SiO2(1.7 nm)/Si-P structure fabricated on 10 Ω.cm substrates using rapid thermal oxidation (RTO) at 850°C. Different thicknesses of glass coverslips were obtained through controlled chemical thinning using BOE (Buffered Oxide Etch; 1HF: 6NH4F) with corrosion time varying from 2 to 12 h followed by a surface chemical treatment with an ammonia-based solution (4H2O: 1H2O2:1NH4OH). Current density x voltage curves (JxV), using indoor light illumination of 11.7 mW/cm2 at 25oC on the sample surface, were extracted for different thicknesses of the processed glass coverslips and the main electrical parameters were obtained for the MOS photovoltaic cells such as the short circuit current (Jsc), the open circuit voltage (Voc) and energy conversion efficiency (η). As a result, a significant increase of the indoor energy conversion efficiency was obtained for the thickness of the glass coverslip of ~98 µm compared to those without chemical thinning (~130 µm thick), this is to say, η ≈ 4.8 – 5.2% against η ≈ 3.3%, respectively.