Self-Limiting Growth of GaAs Surfaces on Non-Planar Substrates

The growth of GaAs epitaxial layers by organometallic chemical vapor deposition on top of V-grooved substrates is found to exhibit a self-limiting behavior. As in the case of the self-limiting growth of AlGaAs on similar patterned substrates, the self-limiting GaAs profile exhibits characteristic crystallographic nanofacets. However, these facets are considerably broader than in typical, self-limiting AlGaAs profiles obtained at similar growth temperatures. Atomic force microscopy in air reveals the three-dimensional structure of the self-limiting GaAs surfaces, showing monolayer steps on the central (100) nanofacets and quasiperiodic modulation caused by step bunching on the side {311}A nanofacets. The width of the self-limiting GaAs V grooves can be reduced to less than 10 nm at sufficiently low growth temperatures, thus providing useful templates for growing, e.g., self ordered InGaAs/GaAs quantum wires.