Aluminum Nanoparticles Passivation of Multi-Crystalline Silicon Nanostructure for Solar Cells Applications

In this paper, we demonstrated that aluminum films deposited on the front surface of multi-crystalline silicon (mc-Si) provide excellent surface passivation and high electronic quality of such materials. A thickness of about 8 μm of aluminum films was deposited by a screen-printed on the front surface of the mc-Si annealed for 20 min at 500 °C. The immersion of multi-crystalline silicon in HF/H2O2/HNO3 after the film deposition is the key factor in achieving the high electronic quality front surface of mc-Si nanostructures (mc-Si-NS). As a result, the total reflectivity drops to about 2% and a low surface recombination velocity of about 1.5 cm s−1 was obtained. These results indicate that multi-crystalline silicon surface passivation using the aluminum layer is a valuable process to improve the efficiency of the mc-Si-NS based solar cells.