AVS 49th International Symposium
    Thin Films Wednesday Sessions
       Session TF-WeP

Paper TF-WeP4
Fabrication of ZnO Thin Films by Pulsed Laser Ablation with Remote Radical Source

Wednesday, November 6, 2002, 11:00 am, Room Exhibit Hall B2

Session: Poster Session
Presenter: T. Suzuki, Meijo University, Japan
Authors: T. Suzuki, Meijo University, Japan
M. Hiramatsu, Meijo University, Japan
N. Shimizu, Meijo University, Japan
Correspondent: Click to Email
Zinc oxide (ZnO) is a II-VI compound semiconductor with wide direct bandgap of 3.3 eV at room temperature. ZnO exhibits good piezoelectric, photoelectric and optical properties, and might be a good candidate for an electroluminescence device such as ultra-violet (UV) laser diode. ZnO films also have potential applications for surface acoustic wave devices and low loss wave-guides. In this study, ZnO thin films have been fabricated on Si (100) substrate at temperatures of 300 - 400°C by pulsed laser ablation using a KrF excimer laser with the wavelength of 248 nm. During the deposition, a remote microwave O@sub 2@/N@sub 2@ plasma as a radical source was used in order to improve the optical quality of the film. We have investigated the effect of the radical source on the optical and structural properties of ZnO films using photoluminescence (PL). From the PL measurement, all the films fabricated with and without using radical source showed a typical luminescence behavior with the two emissions of a narrow UV and a broad visible band. It is reported that the visible luminescence of ZnO was caused by the defects, such as oxygen vacancies and zinc interstitials in the films. As the partial pressure of N@sub 2@ in the microwave O@sub 2@/N@sub 2@ plasma increased, the intensity of UV luminescence increased and that of visible luminescence decreased. From this result, it was suggested that the injection of the nitrogen radicals into plasma plume might be effective to reduce the visible luminescence of ZnO and to improve the optical quality of the film.