Multiple intense pulsed light sintering of silane surface modified Cu oxide nanoparticle paste on Si wafer substrate for solar cell electrode

Abstract

In this study, the effect of copper (Cu) oxide shell type and thickness on the intense pulsed light (IPL) sintering of Cu nanoparticle (NP) paste on silicon (Si) wafer was investigated. The Cu NPs were oxidized in a heating chamber at 100-300°C to demonstrate the IPL sintering characteristics according to the Cu oxide shell. Cu NPs oxidized at a temperature of 300°C were covered in a thick CuO shell, which can be well sintered on a Si wafer with high thermal conductivity by high energy of multiple IPL irradiation without re-oxidation. The oxidized Cu NPs were surface modified using silane dispersant to secure higher electrical conductivity. To observe a mechanism of the multiple IPL sintering process, in-situ resistance monitoring of Cu NPs electrode was conducted. Scanning electron microscopy, x-ray diffraction and x-ray photoelectron spectroscopy were performed to characterize the IPL sintered Cu NPs paste. The thickness of Cu oxide shell was measured using transmission electron microscopy. Also, zeta potential and sedimentation analysis were performed to analyze the dispersion of oxidized Cu NPs. Finally, the Cu NPs paste based electrode was fabricated on Si wafer using multiple IPL irradiation and it exhibited a low resistivity of 8.38 μΩ•cm.