Oxygen modified diamond-like carbon as window layer for amorphous silicon solar cells

► Band gap modification of DLC by oxygen plasma treatment (OPT). ► OPT-DLC as p-layer for a-Si:H p-i-n solar cell. ► Improved efficiency with enhancement in p-layer band gap. ► DLC as hard, protective and encapsulate layer for a-Si:H based p-i-n solar cells.