Demonstration of c-Si Solar Cells With Gallium Oxide Surface Passivation and Laser-Doped Gallium p + Regions

Gallium oxide (Ga₂O₃) 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 × 10¹¹ cm^-2 eV^-1 at midgap. The passivation, as determined by the injection-dependent excess carrier lifetime, is demonstrated to be commensurate to that of PEALD aluminum oxide. In addition, Ga₂O₃ is used as a gallium source in a laser-doping process, resulting in a device efficiency of 19.2% and an open-circuit voltage of 658 mV in a partial rear contact p-type cell design.