Nano-crystalline Sb-based compound semiconductor formed on silicon

A self-assembled InGaSb quantum dot (QD) structure as a nano-structured Sb-based compound structure is fabricated on a silicon substrate using a solid-state molecular beam epitaxy (MBE). A small (dimensions of less than a few tenths of a nanometer) and high-density (>10¹⁰/cm²) InGaSb QD structure can be obtained on a Si wafer surface under optimal growth conditions at a low temperature, which is compatible for use with Si-CMOS processes. Using high-resolution transmission electron microscope (TEM) observation, a clear crystalline lattice image in the fabricated InGaSb QD and the interface between the InGaSb and the Si are successfully observed. Based on these results, we expect that a nano-crystalline Sb-based compound semiconductor on a Si surface will become a useful and novel material system with high crystalline quality, enabling the development of a new generation of integrated photonics and high-speed electron devices on the Si platform.