Rapid growth of zinc oxide polyhedral crystals from whiskers using a shock wave technique

A cylindrically converging shock-wave technique has been applied to investigate rapid growth processes of fine polyhedral crystals of ZnO with the wurtzite structure from the gaseous phase under strongly chaotic conditions. Scanning electron microscopy showed that clear-cut hexagonal plates and pyramids were formed through several stages of development, namely the processes of nucleation, initiation of whisker growth, coalescence of the whiskers into a dense body, and subsequent smoothing of the rough surfaces. The consequent crystal habit was determined by the distribution of whiskers on the crystal surfaces. Twinned crystals were formed by coalescence between the whiskered crystals.