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    Semiconductors Monday Sessions
       Session SC-MoM

Paper SC-MoM7
Metal-organic Vapor Phase Epitaxial Growth and Photoluminescent Properties of ZnMgO and ZnCdO Thin Films

Monday, October 29, 2001, 11:40 am, Room 124

Session: Band-Engineered Electronic Materials
Presenter: W.I. Park, Pohang Univ. of Science and Technology, Korea (ROK)
Authors: W.I. Park, Pohang Univ. of Science and Technology, Korea (ROK)
G.-C. Yi, Pohang Univ. of Science and Technology, Korea (ROK)
Correspondent: Click to Email
ZnO, a wide-gap semiconductor oxide, has attracted considerable attention due to its large exciton binding energy (~60 meV) and bond strength, which might make reliable high efficiency photonic devices based on ZnO. Recently it has also been reported that ZnMgO was grown with maximum Mg incorporation up to 36 at.% without phase separation and that the room temperature luminescence energy in this film blue-shifted from 3.3 to 4.0 eV. Since a ZnMgO containing MgO over 4 at.% is in a thermodynamically metastable state, this result indicates that the solubility limit of Mg in ZnO depends on growth mechanisms as well as growth conditions. Meanwhile, current research on the growth of ZnO-related alloys is restricted to pulsed laser deposition and molecular beam epitaxy. Despite the epitaxial growth of high quality ZnO and related alloys using the methods, they might have disadvantages in mass production, due to high cost and low throughput. In this talk, we demonstrate that metal-organic vapor phase epitaxy (MOVPE), which has great advantages in terms of large area deposition and atomic composition control feasibility, is an excellent technique for the epitaxial growth of high quality ZnO and related alloy films. In addition, the structural and optical characterizations of ZnMgO and ZnCdO thin films will be reported. By increasing Mg content up to 47 at.%, the c-axis constant of ZnMgO films decreased from 0.521 nm to 0.515 nm and no significant phase separation in the ZnMgO films was observed as determined by x-ray diffraction measurements. Furthermore, the near-band-edge (NBE) emission peak position showed blue shifts of 100, 430, and 570 meV at Mg content levels of 9, 21, and 47 at.%, respectively. Photoluminescent properties of the ZnMgO and ZnCdO alloy films will also be discussed.