Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10669698 | Thin Solid Films | 2014 | 5 Pages |
Abstract
Non-doped MgxZn1 â xO films (MgxZn1 â xO films) and nitrogen-doped MgxZn1 â xO films (MgxZn1 â xO:N films) were grown epitaxially on Zn faces of ZnO single crystal substrates by the plasma-assisted reactive evaporation (PARE) method using ZnMg alloys. Optical parameters, refractive index n, extinction coefficient k, and absorption coefficient α of these films and ZnO substrate were easily estimated by variable angle spectroscopic ellipsometry. The k values of these films abruptly increased with increase in photon energy near the absorption edge region. Dispersions of n of these films were sharper with larger peak values than that of a ZnO substrate. MgxZn1 â xO films and MgxZn1 â xO:N films grown on a ZnO substrate by the PARE method are of high quality with less defects than those of a ZnO substrate. Maximum value of α of these films calculated from k was about 2 Ã 105 cmâ 1. The values of intercepts on photon energy hν axis of (αhν)2âhν plots for these films and the ZnO substrate agree with peak energy of PL spectra, the origin of which is free excitons. These results indicate that absorption in those materials is dominated by exciton absorption.
Related Topics
Physical Sciences and Engineering
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Authors
Takami Abe, Akira Nakagawa, Michiko Nakagawa, Tetsuya Chiba, Shuzo Takahashi, Yasuhiro Kashiwaba, Shigeki Chiba, Tsutomu Ojima, Katsumi Aota, Masahiro Daibo, Hiroshi Osada, Tamiya Fujiwara, Ikuo Niikura, Yasube Kashiwaba, Kouichi Tsutsumi, Michio Suzuki,