title: Thermally controlled widening of droplet etched nanoholes.
abstract: We describe a method to control the shape of nanoholes in GaAs (001) which combines the technique of local droplet etching using Ga droplets with long-time thermal annealing. The cone-like shape of inverted nanoholes formed by droplet etching is transformed during long-time annealing into widened holes with flat bottoms and reduced depth. This is qualitatively understood using a simplified model of mass transport incorporating surface diffusion and evaporation. The hole diameter can be thermally controlled by varying the annealing time or annealing temperature which provides a method for tuning template morphology for subsequent nanostructure nucleation. We also demonstrate the integration of the combined droplet/thermal etching process with heteroepitaxy by the thermal control of hole depth in AlGaAs layers.
authors.affiliation: Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Jungiusstraße 11, Hamburg 20355, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Heyn
authors.affiliation: Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Jungiusstraße 11, Hamburg 20355, Germany.
authors.forename: Sandra
authors.initials: S
authors.lastname: Schnüll
authors.affiliation: School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA, UK.
authors.forename: David E
authors.initials: DE
authors.lastname: Jesson
authors.affiliation: Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Jungiusstraße 11, Hamburg 20355, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Hansen
keywords: Droplet etching; Nanostructuring; Self-assembly; Semiconductor