Embodiments of the invention generally provide methods for forming amorphous silicon-based photovoltaic devices, such as solar cells, by utilizing deposition and plasma treatment steps during a plasma-enhanced chemical vapor deposition (PE-CVD) process. In one embodiments, the method includes exposing a transparent conductive oxide (TCO) layer disposed on a substrate to hydrogen plasma during pretreatment, forming a p-type α-Si film on the TCO layer, forming an α-Si intrinsic film on the p-type α-Si film during a PE-CVD process, and forming an n-type α-Si film on the α-Si intrinsic film. In some examples, the PE-CVD process includes depositing an α-Si intrinsic layer during a deposition step, treating the α-Si intrinsic layer to form a treated α-Si intrinsic layer during a plasma treatment step, and sequentially repeating the deposition step and the plasma treatment step until obtaining a desired thickness of the α-Si intrinsic film containing a plurality of treated α-Si intrinsic layers.