Properties of phosphoric acid doped crystalline silicon with different light-trapping schemes for solar cells

Abstract

Properties of phosphoric acid (H3PO4)-doped crystalline silicon (c-Si) with different light-trapping schemes have been investigated for solar cells. Microtextures, b-Si nanotextures, and hybrid textures are fabricated using sodium hydroxide (NaOH) and metal-assisted wet chemical etching (MACE). MACE has been achieved via 30 s of silver nanoparticles (Ag NPs) deposition in a solution of 4.8 M HF:18 mM AgNO3 and 20 s etching in a solution of HF:H2O2:DI H2O (2:1:5). Spin coating of H3PO4 (15% by volume) and Butanol (C4H10O; 75% by volume) on planar c-Si, microtextures, b-Si nanotextures, and hybrid textures is adopted to realize the front junction for the solar cells. Hybrid textures with nanotextures' heights of ∼450–550 nm and widths of ∼80–100 nm on microtextures present a weighted average reflection (WAR%) of 8.3% and an estimated junction depth of about ∼450 nm after the diffusion process. Sheet resistance (Rs) of 148 ± 1.3 Ω/□, carrier concentration (ne) of −6.01 × 1018 cm−3, and carrier mobility (μe) of 140.7 cm2/Vs is obtained for the hybrid textures. Solar cell with hybrid texturing achieves a maximum short-circuit current density (Jsc(max)) of 10.7 mA/cm2 owing to enhanced light-trapping, which results from optimum absorption. Open-circuit voltage (Voc), fill factor (FF), and efficiency (EFF) of 640 mV, 0.36, and 2.5% have been obtained for the hybrid textures solar cell compared to 600 mV, 0.34, 1.7% achieved in the b-Si nanotextures solar cell, respectively.