Material properties of hydrogenated silicon n-layer and their impact on amorphous silicon (a-Si:H) solar cell are studied. By optimizing deposition parameters, mixed-phase n-layer with nanometer-sized Si crystallites embedded in a-Si:H matrix can be obtained, which demonstrates higher conductivity, lower activation energy and wider bandgap. Incorporating the mixed-phase n-layer into a-Si:H cell can significantly improve the open circuit voltage (V-oc) up to 0.95 V, which is approximately 50 mV or 100 mV higher than those cells with a-Si:H n-layer or microcrystalline silicon n-layer, respectively. The possible explanations of V-oc enhancement brought by the mixed-phase n-layer have also been discussed. Up to now, we have achieved an initial efficiency of 9.4% with high V-oc of 0.945 V, FF of 0.70 and J(sc) of 14.2 mA/cm(2) with a-Si:H i-layer thickness of 300 nm and substrate temperature as high as 220 degrees C. (C) 2014 Elsevier B.V. All rights reserved.