Demonstration of c-Si solar cells with gallium oxide surface passivation and laser-doped gallium p+ regions

摘要

Gallium oxide (GaO) deposited by plasma enhanced atomic layer deposition (PEALD) is shown to passivate crystalline silicon surfaces via a combination of a high negative charge and a reduction in the density of surface defects to below 1×10 cm eV at midgap. The passivation, as determined by the injection dependent excess carrier lifetime, is demonstrated to be commensurate to that of PEALD aluminium oxide (AlO). In addition, GaO is used as a gallium source in a laser doping process, resulting in an efficiency of 19.2% and an open circuit voltage of 658 mV in a partial rear contact p-type cell design. As such, we demonstrate that GaO is comparable to AlO in terms of performance and utility, with potential material advantages over AlO.