| AVS 58th Annual International Symposium and Exhibition | |
| Transparent Conductors and Printable Electronics Focus Topic | Thursday Sessions |
| Session TC+AS+EM-ThM |
| Session: | Transparent / Printable Electronics Part 1 |
| Presenter: | Hisao Makino, Kochi Univ. of Tech., Japan |
| Authors: | H. Makino, Kochi Univ. of Tech., Japan T. Shibata, NIMS, Japan N. Yamamoto, Kochi Univ. of Tech., Japan T. Sasaki, NIMS, Japan T. Yamamoto, Kochi Univ. of Tech., Japan |
| Correspondent: | Click to Email |
Ga-doped ZnO (GZO) film is one of promising candidates as substitute for ITO transparent electrodes in optoelectronic devices. Control of structural properties, especially c-axis orientation, is crucial issue to improve electrical properties of polycrystalline GZO films on glass or plastic substrates [1]. Recently, nanosheet seed layers were proposed to control crystal orientation of oxide films on amorphous substrates [2]. In this study, we employed a seed layer of tungsten oxide nanosheets with two-dimensional hexagonal lattice structure for deposition of GZO thin films on unintentionally heated glass substrates.
The nanosheets were assembled on glass substrates by Langmuir-Blodgett method. The GZO films with thickness of 100 nm were deposited by an ion-plating with direct current arc discharge on unintentionally heated glass substrates with and without the nanosheet seed layers.
The crystal structural properties were characterized by x-ray diffraction measurements. The c-axis orientation of the GZO films was drastically enhanced by the nanosheet seed layers. The intensity of (002) diffraction peak of GZO films deposited with the seed layers was about 40 times as strong as that deposited without the seed layers. The degree of c-axis orientation was evaluated by the (002) x-ray rocking curve (XRC). The full-width half-maximum of XRC of the GZO films on the nanosheet seed layers was 2.6 °, which is even lower than that of GZO films deposited on bare glass substrate at 200 °C.
The electrical properties were characterized by Hall effect measurements at room temperature. The GZO films deposited on the nanosheet seed layers showed the resistivity of 2.9 x10-4 Ωcm with the Hall mobility of 24 cm2/Vs and the carrier concentration of 9.0×1020 cm-3. On the other hand, the GZO film deposited without the nanosheet seed layers showed the resistivity of 5.0 x10-4 Ωcm with the Hall mobility of 17 cm2/Vs and the carrier concentration of 7.2×1020 cm-3. Both the Hall mobility and the carrier concentration were improved by the nanosheet seed layers.
[1] T. Yamada et al., J. Appl. Phys. 107, 123534 (2010). [2] T. Shibata et al., Adv. Mater. 20, 231 (2008).