The Properties of Surface Textured ZnO:Al Films for Thin Film Solar Cells
|Jinsu Yoo 1, Jeongchul Lee 2, Seokki Kim 2, Kyunghoon Yoon 2, I Jun Park 2, Suresh Kumar Dhungel 1, Bojan Karunagaran 1, Devanesan Mangalaraj 1, Junsin Yi 1|
1. Sungkyunkwan University, School of Information and Communication Engineering, 300 Chunchun-dong, Jangan-gu, Suwon 440746, Korea, South
Aluminium doped Zinc Oxide (ZnO:Al) films were deposited by rf magnetron sputtering from a ZnO target mixed with Al2O3 of 2.5 % on to glass substrates maintained at different temperatures ranging from 300 to 673 K. Argon gas pressure during the deposition was in the range 0.3-10 mtorr. Structural, optical and electrical properties of the prepared films have been characterized. As the argon gas pressure was increased, the deposition rate was found to decrease and the surface roughness was increased. Furthermore the carrier concentration and the Hall mobility were decreased and thus the electrical resistivity increased. Depending on their structural properties these films develop different surface structures upon post deposition etching in diluted HCl (0.5%). The light scattering properties of suitable film can be controlled over a wide range simply by varying the etching time, substrate temperature and argon pressure. The X-Ray diffraction (XRD) studies showed that the films are highly oriented with their crystallographic c-axis perpendicular to the substrate almost independent of argon pressure and also an improvement in crystallanity for the films deposited at higher temperature was observed. Measurements of transmission spectra reveal that ZnO:Al films have an average transmission of over 85 % in the wavelength range of 400 - 800 nm. Also the films showed an excellent electrical resistivity 1.9 x 10-4 ohm-cm, a value comparable to that for indium tin oxide film presently used as a transparent electrode.
Presentation: poster at E-MRS Fall Meeting 2004, Symposium F, by Jinsu Yoo
See On-line Journal of E-MRS Fall Meeting 2004
Submitted: 2004-04-30 08:15 Revised: 2009-06-08 12:55