Growing GaAs Nanowires on Silicon: A Closer Look

Growing III-V nanowires (NW) on silicon (Si) substrates is a tricky task. Scientists often rely on guesswork and different interpretations of important steps, like preparing the sample and forming the Au-Si alloy in the growth reactor. To make high-performance electronic devices that combine the best properties of III-V NW semiconductors with silicon technology, we need to solve these challenges. Using Metalorganic Chemical Vapor Deposition (MOCVD) and Environmental Transmission Electron Microscopy (ETEM-MOCVD), researchers can better understand the growth process. This study shows how Au-catalyzed GaAs NWs were successfully grown on Si(111) substrates using micro-electromechanical system (MEMS) chips with monocrystalline Si-cantilevers.MOCVD helped tune the initial parameters, while ETEM-MOCVD provided insights into early nucleation and how the catalyst interacts with the substrate. The study found that removing native oxide layers and forming the Au-Si alloy greatly affects nucleation. Three typical configurations of NW "roots" were identified, each influenced by growth conditions and preparation steps. This affects the structure and potentially the optical properties of the NWs. Doping from the Si-substrate might affect both optical and electrical properties, but no Si traces were found in the NWs after nucleation, only a small amount in the catalytic droplet. In situ studies are crucial for understanding nucleation mechanisms, which can help optimize III-V NW growth on Si substrates and develop high-performance III-V/Si devices.