Morphological control and structural characteristics of crystalline Ge–C systems: Carbide nanorods, quantum dots, and epitaxial heterostructures

Abstract

Chemical precursors are used to grow crystalline Ge–C materials with unusual morphologies that depend on the molecular design of the precursor and the C concentration. Ge–C nanorods with overall C content of about 13–15 at. % and lattice constants close to that of pure Si grew very rapidly from the surface of a 40 nm Ge–C epitaxial film. Coherent carbide islands are formed after epitaxial growth of 20 nm Ge1−xCx (x=9 at. %) on (100)Si. Lower reaction temperatures resulted in extremely low growth rate of epitaxial Ge1−xCx (x=3–5 at. %) heterostructures with very flat surfaces implying two-dimensional layer-by-layer growth. The use of precursor chemistry as reported here to control morphology and composition in the Ge–C system may provide a simple and reliable synthetic route to a new family of Si-based heterostructures.