title: Transparent films for heterojunction Si photovoltaics.
abstract: A heterojunction of Al-doped ZnO (AZO) and Si was applied as a photodiode. A Co-sputtering system was used to deposit a quality AZO film following an n-type Si thin film coating. Al is an n-doping element for ZnO and thus the Al content significantly controls the mobility and the crystalline structure of AZO films. In order to provide the highest mobility, the optimum Al-content was found to be 5.22 wt%. X-ray diffraction analysis also showed a release of the compressive stress for the Al-5.22 wt% AZO film. Due to the excellent electrical conductivity of the AZO film, the heterojunction diode showed an enhanced rectifying ratio of 87.7 from 59.9 of the bare Si diode according to the reduction of the series resistance. This scheme may provide a route to reducing the contact resistance and subsequently improving photovoltaic devices.
authors.affiliation: Department of Electrical Engineering, Kunsan National University, Kunsan 753701, Korea.
authors.forename: Joondong
authors.initials: J
authors.lastname: Kim
authors.forename: Yun Chang
authors.initials: YC
authors.lastname: Park