Hydrothermal growth and characterization of ZnO crystals

ZnO crystals with dimensions of 30×38×8 mm3 have been grown by the hydrothermal method using a mixed solution of KOH, LiOH and H2O2. The growing rates for +c(0 0 0 1) and −c(0 0 0 1¯) were 0.17 and 0.09 mm/day, respectively. The crystal color was very light green for +c sector and dark brown for −c sector. For the +c sector, the resistivity at room temperature was 80 Ω cm, the carrier concentration was about 104/cm3, and the mobility was about 100 cm2/V s. The full-width at half-maximum (FWHM) of double axis X-ray rocking curve for the polished Zn face cut from +c sector was 45 arcsec. The photoluminescence (PL) spectrum and the absorption spectrum of +c part of the crystals at room temperature were also reported and discussed in this paper.