Growth and characterization of ZnO single crystals with hydrous KOH melt method

Abstract

Transparent, brown-green and brown wurtzite zinc oxide (ZnO) single crystals were grown in silver, nickel and iron crucibles separately by the spontaneous nucleation method using hydrous KOH melt as flux. The analysis results of X-ray diffraction and inductively coupled plasma atomic emission spectrometry indicate that the color of the crystals is related to the impurities contained in them that come from the crucibles. In addition, photoluminescence (PL) spectrometry was also employed to characterize the crystals. The results exhibite that the ZnO crystals grown from the silver crucible have high quality, and its PL spectrum excitated by wavelength of 325 nm at room temperature displays the strong ultraviolet emission at 381 nm from the band edge. On this basis, a large ZnO crystal 3 mm in diameter and 34 mm long was grown in a 200 mL silver crucible.