Lowest surface recombination in n-type oxidised crystalline silicon by means of extrinsic field effect passivation

Surface recombination remains a major factor limiting the efficiency of silicon solar cells. The post-processing of dielectric films used as surface coatings has been previously demonstrated an effective technique to improve their passivation quality. In this paper extrinsic methods are demonstrated to produce the lowest reported surface recombination velocity in solar relevant n-type silicon. Recombination velocities below 2.8 cm/s at an injection of 1015 cm-3, are achieved using extrinsic field-effect passivation, or < 0.6 cm/s when using combined extrinsic chemical and extrinsic field effect passivation. These are equivalent to emitter saturation current densities J0e<1.4 fA/cm2 and 0.6 fA/cm2.