Investigating the Potential of Hydrogen Plasma Treated ALD-TiOx Films as Hole-selective Passivating Contacts in Crystalline Silicon Solar Cells

The potential of hydrogen plasma treated atomic layer deposited (ALD) titanium oxide (TiOx) films as hole-selective passivating contacts in crystalline silicon (c-Si) solar cells is discussed from three aspects including the passivation quality, carrier selectivity and electrical property. In this work, we also propose an integrated deposition technique through incorporating hydrogen plasma pulses into the thin film deposition. The passivation quality, carrier selectivity and electrical property were studied through photoluminescence (PL) image analysis, Schottky barrier height analysis using dark current-voltage/capacitance-voltage (I-V/C-V) measurements and contact resistivity analysis using transmission line method (TLM). Compared with conventional deposition techniques and post-treatments, high passivation quality, excellent carrier selectivity and low contact resistivity can be achieved through combining our integrated deposition technique with post hydrogen plasma treatment (HPT). Further study will be performed to evaluate the durability and reliability of TiOx contacts in c-Si solar cells. Index Terms-atomic layer deposition, titanium oxide, passivation quality, carrier selectivity, contact resistivity, passivating contact, hole-selective contact, hydrogen plasma