Growth and characteristics of hydrogenated In-doped ZnO thin films by pulsed DC magnetron sputtering

We investigated the role of hydrogen impurities in highly oriented In-doped ZnO (IZO:H) films. The conductivity of ZnO:H films exhibit small variation despite the increase of hydrogen ratio. The small variation of the carrier concentration in IZO:H films can be explained by the reduction of the oxygen deficiency for the charge neutrality and the increase of Vzn-H bonding for partially charge compensation in the films. The additional mode at 573 cm−1 is interpreted as vacancy clusters. The discrepancy between the increase of vacancy clusters (573 cm−1) and small variation of carrier concentration is attributed to the different physical characteristics of the IZO:H films due to the hydrogen existence between bulk and surface. The measured FT-IR peak at 3500 cm−1 exhibits typical characteristic of O-H bonding.