Analysis of front metal contact for plated Ni/Cu silicon solar cell

Abstract

Commercial solar cells with screen printed front contacts are formed by using Ag paste. This has caused high shading loss and low conductivity because of high contact resistance. One of the front metal contact solar cells is Ni/Cu metal contact, made by using plating that is easily available so as to allow simple and inexpensive production techniques to be applied to mass production. Ni has been shown to be a suitable barrier to Cu diffusion into the silicon. Also, it is possible to use Ni silicide for the sintering process. Ni silicide has been reported have compositions of Ni₂Si (200°C ∼ 300°C), NiSi (300°C ∼ 700°C), and NiSi₂ (700°C ∼ 900°C). Especially, NiSi has been shown to have low contact resistance (14 ∼ 16 mW·cm) between surface and electrode. Finally, Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray spectroscopy (EDX) analysis show experimental results in which electroless plating of Ni and Ni silicide can be seen. The efficiency of plated Ni/Cu contact solar cells was improved by 0.8% over that of screen printed solar cells.