Effects of impact conditions on the electrical and mechanical properties of supersonic cold sprayed Cu–Ni electrodes

Supersonic cold sprayed Cu and Ni particles were deposited on Si wafers for potential use as solar-cell front electrodes. Line-printed Ni–Cu electrodes were successfully fabricated with thicknesses between 30 and 50 μm. Choice of carrier gas (nitrogen and air) and effects of particle size and impact velocity on the electrical and mechanical properties of these Ni–Cu electrodes were quantified. The carrier gas had no discernable effect on electrode properties while increased particle sizes slightly decreased electrode specific resistivities. Impact velocity had the most pronounced influence on electrode electrical properties. Both the contact and specific resistivities decreased nearly linearly with increasing impact velocity. Adhesion strength was measured with a STAB-TEST instrument and found sufficient for all measured electrodes. The electrodes were further characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and auger electron spectroscopy.