Open Access Nano Express

Fundamental role of arsenic flux in nanohole formation by Ga droplet etching on GaAs(001)

David Fuster*, Yolanda González and Luisa González

Author Affiliations

Instituto de Microelectrónica de Madrid (IMM-CNM, CSIC), Isaac Newton 8, Tres Cantos, Madrid 28760, Spain

For all author emails, please log on.

Nanoscale Research Letters 2014, 9:309  doi:10.1186/1556-276X-9-309

Published: 18 June 2014

Abstract

Nanoholes with a depth in the range of tens of nanometers can be formed on GaAs(001) surfaces at a temperature of 500°C by local etching after Ga droplet formation. In this work, we demonstrate that the local etching or nanodrilling process starts when the Ga droplets are exposed to arsenic. The essential role of arsenic in nanohole formation is demonstrated sequentially, from the initial Ga droplets to the final stage consisting of nanoholes surrounded by ringlike structures at the surface and Ga droplets consumed. The kinetics of local etching depends on the arsenic flux intensity, while the ringlike structures are basically the same as those formed underneath the droplets in the absence of arsenic. These structures show motifs with well-defined crystalline facets that correspond to those expected from surface energy minimization. These experimental results are qualitatively analyzed for a better understanding of the nanohole formation underlying processes.

Keywords:
Droplet epitaxy; Quantum dots; Nanopatterning