ABSTRACT
This research investigates the impact of screen printing silver (Ag) with phosphoric acid (H3PO4) as a metallic dopant paste on etched versus non-etched thermally grown silicon dioxide (SiO₂) layers used as passivating contacts in silicon solar cells. The combination of Ag and phosphorous (P) from H3PO4 is denoted as Ag/P metallic dopant paste. Passivating contacts are crucial for reducing recombination losses and improving solar cell efficiency. Thermally grown SiO₂ layers are commonly used due to their excellent passivation properties and compatibility with silicon substrates. The study involves a comprehensive comparison of the performance of etched and non-etched SiO₂ layers, including the activation of P from H3PO4 and series resistance. The methodology involves the thermal growth of SiO₂ layers on silicon wafers, followed by selective etching on a subset of the samples. Subsequently, Ag/P is deposited on both etched and nonetched SiO₂ layers using the screen printing technique. The samples undergo annealing using a round quartz furnace to form the passivating contacts. The dark current-voltage measurements are employed to evaluate the activation of P, series resistance and the behaviour of the screen-printed n-type silicon (n-Si). The results reveal the activation of P from Ag/P when adding more H3PO4 with Ag paste. The etched SiO₂ layers also exhibited lower total current and an onset between semi-ohmic and ohmic behaviour. Meanwhile, the Ag and Ag/P screen-printed on SiO₂ layers revealed higher total current but exhibited an onset between leaky-diode and ohmic behaviour. Specifically, the etched SiO₂ layers demonstrated improved surface passivation quality, evidenced by lower surface recombination velocities.
DOWNLOAD