Synthesis of ZnO microwires and tetrapods by optical furnace

Abstract

In this study, a new route is described in order to obtain wires which can reach a few hundreds of micrometers long. ZnO rod is sintered at 900°C for 10h in air. Then the centimetric rod is placed in an optical furnace. The optical furnace allows to reach a thermal gradient of about 350°C/cm. In a first step, the vaporization of ZnO occurs, and in a second step the condensation of ZnO on the rod appears and leads to the growth of ZnO microwires (MWs). In few minutes, the MWs can reach in the c-direction a dimension higher than 100μm with a diameter close to ten microns. The shape of the MWs is hexagonal which is consistent with the crystal structure of ZnO (P63mc group). The MWs exhibit a high crystalinity.