We investigated intentionally hydrogenated zinc oxide (ZnO:H) fabricated by combining photoassisted metalorganic chemical vapor deposition and mercury-sensitized hydrogen addition methods. We found that intentionally incorporated hydrogen plays an important role in n-type conduction as a donor, improving free carrier concentration and electrical stability. We simultaneously obtained improved surface roughness of the ZnO:H film due to an enhancement of (11 (2) over bar0) orientation. The high-quality ZnO:H film is promising as a back reflector material for thin-film solar cells. (C) 2003 American Institute of Physics.