Lateral growth and optical properties of ZnO microcrystal on sapphire substrate

Without catalysis, hexagonal zinc oxide (ZnO) microcrystals were successfully grown on (0 0 0 1) sapphire substrate in a home made chemical vapor deposition system under atmospheric pressure. A rapid lateral growth at rate of 15 μm/h and a dense growth of ZnO crystals were realized in the growth regions of 800 and 850 °C, respectively. The growth mechanisms were explained similarly with the selective epitaxy. The high quality of the crystals was attested by the X-ray diffraction pattern, Raman scattering and temperature dependent photoluminescence. These results showed the potential of lateral growth ZnO crystals at low cost.

► Hexagonal ZnO crystals were synthesized in a chemical vapor deposition system.
► A rapid lateral epitaxy growth mode of ZnO crystal was realized.
► The ZnO nucleation density was increased in low temperature growth region.
► The sharp ultraviolet emission at 378 nm indicated the high quality of ZnO crystal.