Lattice relaxation mechanism of ZnO thin films grown on c-Al{sub 2}O{sub 3} substrates by plasma-assisted molecular-beam epitaxy
- Center for Interdisciplinary Research, Tohoku University, Aramakiazaaoba, Aoba-ku, Sendai 980-8578 (Japan)
We report on the lattice relaxation mechanism of ZnO films grown on c-Al{sub 2}O{sub 3} substrates by plasma-assisted molecular-beam epitaxy. The lattice relaxation of ZnO films with various thicknesses up to 2000 nm is investigated by using both in situ time-resolved reflection high energy electron diffraction observation during the initial growth and absolute lattice constant measurements (Bond method) for grown films. The residual strain in the films is explained in terms of lattice misfit relaxation (compression) at the growth temperature and thermal stress (tension) due to the difference of growth and measurement temperatures. In thick films (>1 {mu}m), the residual tensile strain begins to relax by bending and microcrack formation.
- OSTI ID:
- 21016194
- Journal Information:
- Applied Physics Letters, Vol. 91, Issue 23; Other Information: DOI: 10.1063/1.2813021; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
Similar Records
Impacts of anisotropic lattice relaxation on crystal mosaicity and luminescence spectra of m-plane Al{sub x}Ga{sub 1-x}N films grown on m-plane freestanding GaN substrates by NH{sub 3} source molecular beam epitaxy
Interface structure and anisotropic strain relaxation of nonpolar wurtzite (1120) and (1010) orientations: ZnO epilayers grown on sapphire