Passivating/hole-selective contacts based on V2O5/SiOx stacks deposited at ambient temperature

N-Type crystalline silicon (c-Si) heterojunctions with V2O5/SiOx stacks as passivating/hole-selective contacts are reported. SiOx interlayers were prepared by low temperature (T<110 ºC) oxidation processes, followed by thermal evaporation of V2O5 at ambient temperature. A high surface passivation, with an implied open-circuit voltage (i-VOC) of 675 mV, is obtained for a 2.1 nm thick SiOx interlayer 'naturally' formed during V2O5 evaporation. X-ray photoelectron spectroscopy analyses indicate a sub-stoichiometric configuration (SiOx~1.4), whereas hydrogen-containing species like Si-OH and Si-(O3H) are identified by secondary ion-mass spectroscopy as possible contributors to dangling bond passivation. A conversion efficiency of 16.5% (VOC = 642 mV) is attained, confirming the potential of these dopant-free novel structures for c-Si photovoltaics.