Aluminum rich zinc oxide (AZO) film was made on silicon substrates by spin coating using a precursor containing Al and Zn in the 20% atomic ratio. The films were annealed in air atmosphere and in hydrogen ambient. The minimum reflectance (R-lambda) in air annealed (AZO:Air) samples was similar to 2.5% in the vicinity (+/- 50 nm) of 750 nm, however, the value was marginally lower (similar to 2%) in hydrogen annealed (AZO:H-2) samples. The average R-lambda over 300-1200 nm range was 18.5% and 14.1% respectively. An additional XRD peak of H2Al10O16 at 2 theta = 51.50 degrees corresponding to (1 2 1) reflection plane was observed in the AZO:H2 film. The AZO films were applied on the front and back surfaces of bifacial crystalline silicon (c-Si) solar cells where an improvement both in short circuit current density (J(sc)) and open circuit voltage (V-oc) was observed. The values of J(sc) and V-oc after AZO:Air were increased by 23% and similar to 10 mV respectively w.r.t without AZO layer cells which on subsequent annealing in H-2 raised to 32% and similar to 21 mV. J(sc) (AZO:Air) was used to calculate the expected enhancement in V-oc which matched with the measured increase in V-oc. The improvement in J(sc) is due to reduced reflectance and, hence, the observed increase in V-oc (AZO:Air) is attributed to it. On the other hand, increase in V-oc after AZO:H-2 step was much more and cannot be accounted only by R-lambda, and therefore, the additional enhancement in V-oc is attributed to back surface passivation that has occurred after annealing of the solar cells in hydrogen ambient. This attribution is substantiated by the internal and external quantum efficiencies (IQE and EQE) after back and front illumination of the solar cells and minority carrier lifetime measurements. The IQE data was used to calculate the diffusion length (L-n) of the base region where the value of L-n did not change after AZO:Air layer (=130 mu m for Cell #1) but its value substantially increased (=244 mu m) after the AZO:H-2 treatment. This observation further reiterates our claim that the AZO film has surface passivation property. (C) 2013 Published by Elsevier Ltd.