Effect of Growth Conditions on Morphology and Photoluminescence Properties of ZnO Nanowires Fabricated by Thermal Evaporation without a Metal Catalyst

Abstract

We demonstrate that single crystalline ZnO nanowires with large length/diameter ratio are successfully grown on Si, glass, and Si with ZnO seed layer via simple thermal vapor deposition, without introducing any catalyst or additive. In this work, we study impact of growth conditions such as growth temperature, substrates, and ZnO seed layer on morphology and photoluminescence properties of ZnO nanowires, in terms of systematic characterizations. The investigations show that the growth temperatures have substantial effect on the morphology of ZnO nanowires, while substrates have low impact. And 700 °C is believed to be the optimized growth temperature among the series of temperatures. Moreover, ZnO seed layer plays an important role in the uniformity and reproducibility of ZnO nanowires growth. PL measurements for the ZnO nanowires exhibit two emission bands including a UV emission and a blue emission, respectively. Finally, the growth behavior of the ZnO nanowires is discussed based on the VS growth mechanism. Our resluts have made a positive progress toward improving control of the morphology of ZnO nanowires.