Formation of quasi-single-crystal Ge on plastic by nucleation-controlled Au-induced layer-exchange growth for flexible electronics

A low-temperature (≤250^oC) formation technique of orientation-controlled large-grain Ge thin films on insulator is desirable for realization of advanced flexible electronics. To achieve this, the Au-induced crystallization technique combined with inter-diffusion-control and interface-energy-modulation techniques has been investigated. Consequently, selective formation of (111)-or (100)-oriented large-grain (>20 μm) Ge crystals on insulator have been realized. Moreover, formation of (111)-oriented large-grain Ge crystals directly on plastic substrates is demonstrated. This technique facilitates realization of future flexible electronics.