MATERIALS SCIENCE AND ENGINEERING SEMINAR The Influence of Metal Catalysts on Orientation and Growth of Germanium Nanowires by Luthfia Syarbaini Ph.D. Prelim Exam - Part I Advisor: Prof. C. Handwerker ABSTRACT Germanium (Ge) nanowires for use in transistors and electronic interconnects are being studied due to their one-dimensional growth and low growth temperatures in the presence of metal catalyst particles and appealing properties such as band-gap energy and high carrier mobility. Understanding the orientation effects on growth can potentially lead to the improved control of nanowire geometry and properties. The specific metal catalyst material has been reported to affect the nanowire orientation grown from silicon substrates. Among the various growth methods, such as vapor-liquid-solid (VLS), self-catalytic, and vapor-solid-solid (VSS), VSS growth demonstrates more control of the nanowire growth orientation. In this review, an analysis of the influence of metal catalyst material on orientation for the VSS and VLS methods is performed. Although there have been reports on orientation effects using metal catalysts, there has not been a systematic study of these effects with controlled growth parameters, including substrate, growth temperature and partial pressure. The study proposed here will focus on the influence of gold and copper metal catalyst type on VSS-grown Ge nanowires and their effects on orientation. Of particular interest, the solid Cu metal catalyst transforms into Cu3Ge while the Au metal catalyst does not change phase. The crystal structures of two solid catalysts and their orientation relationships with growing Ge nanowires will be studied to characterize the orientation and the underlying effects on Ge nanowire growth. Date: Monday, November 12, 2012 Time: 3:30 P.M. Place: ARMS 3115 Lisa Stacey Secretary/Development Assistant Purdue University School of Materials Engineering 765/494-4100