| AVS 57th International Symposium & Exhibition | |
| Energy Frontiers Topical Conference | Tuesday Sessions |
| Session EN-TuM |
| Session: | Flexible Solar Cells |
| Presenter: | K. Nagamoto, LINTEC Corporation, Japan |
| Authors: | K. Nagamoto, LINTEC Corporation, Japan Y. Matubayashi, LINTEC Corporation, Japan T. Kondo, LINTEC Corporation, Japan Y. Sato, Kochi University of Technology, Japan H. Makino, Kochi University of Technology, Japan N. Yamamoto, Kochi University of Technology, Japan T. Yamamoto, Kochi University of Technology, Japan |
| Correspondent: | Click to Email |
In this work, we report the structural, electrical and mechanical bending properties of highly transparent conductive Ga-doped ZnO (GZO) films deposited on flexible substrates for use in electrodes for flexible devices. GZO films were deposited on polyester substrates covered with under-coat layers by ion plating deposition with direct-current arc discharge at a temperature of less than 100 degree Celsius (The glass transition temperature (Tg) of polyester substrates are approximately 120 degree Celsius). Polycrystalline GZO films with high (0002) orientation perpendicular to the substrate have obtained. The resistivity of GZO films of a 100 nm thickness on polyester substrates was 5.0 x 10 -4 ohm-cm and the average transmittance of more than 80 % in the visible wavelength region.
The mechanical bending properties of GZO films were investigated by bend test: sheet resistance of GZO films as a function of bending diameter before and after bending was determined by Hall-effect measurement. When the substrate is bent by an external force, the outer side surface experiences tensile stress and inner side surface experiences compressive stress. The analysis of data obtained by the bend test shows that sheet resistance for GZO films at 12 mm bending diameter were 150 ohm/sq. (before bending test : 50 ohm/sq.) for compressive stress direction whereas sheet resistance was 1770 ohm/sq. for tensile stress direction. In addition, the bend test was carried out for GZO films deposited at different process temperature. GZO films deposited at lower substrates temperature exhibit improved bending performance. GZO films deposited on polymer substrates have residual stress including intrinsic stress and thermal stress caused by the difference in thermal expansion coefficient between GZO films and the substrates. The bending property of GZO films can be improved by controlling the residual stress affected by process temperature.
We developed multiple depositions to reduce polymer substrates temperature and obtained the relationship between bending properties of GZO films and process temperature.
The financial support from the Japan Science and Technology Agency is gratefully acknowledged.