Structural and luminescent properties of ZnO epitaxial film grown on Si(1Â 1Â 1) substrate by atmospheric-pressure MOCVD

Epitaxial ZnO thin films have been grown on 2-in diameter Si(1 1 1) substrates by atmospheric-pressure metalorganic chemical vapor deposition. An initial Al layer with a thickness of 10 Å was deposited in order to protect the Si surface from oxidation. The structural property was characterized using a double-crystal X-ray diffractometer, and the photoluminescence spectra were measured using the excitation of 325 nm line of a He-Cd laser. The minimum full-width at half-maximum (FWHM) of the diffraction peak of ZnO(0 0 2) is 0.35° and 0.16° for the ω and ω-2θ scans, respectively. Free-exciton emission with a shoulder at the bound-exciton peak was observed at 10 K. Microscopic images show cracks for the sample of 3.0 μm thickness, and the crack density is about 7.6×102/cm−1. The maximum area of a crack-free triangular region is bout 1756 μm2.