Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Jungiusstraße 11, Hamburg 20355, Germany.
School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA, UK.
Nanoscale Res Lett. 2014 Jun 9;9(1):285. doi: 10.1186/1556-276X-9-285. eCollection 2014.
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.
我们描述了一种在 GaAs(001)上控制纳米孔形状的方法，该方法结合了使用 Ga 液滴进行局部液滴蚀刻的技术和长时间的热退火。液滴蚀刻形成的倒锥形纳米孔在长时间退火过程中会转变为底部平坦、深度减小的扩宽孔。使用包含表面扩散和蒸发的简化质量传输模型可以定性地理解这一点。通过改变退火时间或退火温度来控制孔直径，从而为随后的纳米结构成核提供了一种调整模板形态的方法。我们还通过在 AlGaAs 层中控制孔深来展示了组合液滴/热蚀刻工艺与异质外延的集成。
