ZnO bulk growth in hydrogen atmosphere

Zinc oxide crystals were grown from the vapor in silica glass ampoules using ‘classic’ and ‘contactless’ growth methods. The stable growth rate in both methods was maintained by continuous flow of the hydrogen and was controlled by partial pressure of the zinc vapor. The morphology of the crystallization front was studied. A tendency to grain selection and growth of a high quality single crystal were found to be dependent on the ratio of hydrogen to zinc pressures. Three kinds of instability resulting from constitutional supersaturation, gas dynamics and surface kinetics were observed on the surface of the crystallization front in various stages of the crystal growth.