Electrical and morphological study of screen printed silicon solar cells contacts

Abstract

The screen printed contact quality influences directly the mono-crystalline silicon solar cells efficiency. This is the aim of this study. A batch of mono-crystalline silicon wafers have undergone all the technological processes such as chemical cleaning, phosphorus diffusion and finally screen printing metallization. According to the used silver paste technical data, the firing temperature should not be greater than 750°C. This is why for this last step, a temperature swept from 650°C to 750°C has been carried out. The principal purpose of this work is to evaluate the Ag/N+ front contact quality by identifying the specific contact resistance, the resistivity and the morphology of each temperature profile. Transmission line method (TLM) is used as the technique for photovoltaic electrical characterization. It has been found that the best annealing temperature profile is750°C which corresponds to the lowest specific contact resistivity value of 1.65 mcm2. Morphological study shows low contact porosity at 750°C which reflects its good quality