Open Access Nano Express

The Investigation of Intermediate Stage of Template Etching with Metal Droplets by Wetting Angle Analysis on (001) GaAs Surface

AA Lyamkina12*, DV Dmitriev1, Yu G Galitsyn1, VG Kesler1, SP Moshchenko1 and AI Toropov1

Author Affiliations

1 Rzhanov Institute of Semiconductor Physics SB RAS, Acad. Lavrent'eva Ave. 13, 630090 Novosibirsk, Russia

2 Novosibirsk State University, Pirogova 2, 630090 Novosibirsk, Russia

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Nanoscale Res Lett 2011, 6:42  doi:10.1007/s11671-010-9790-z

Published: 28 September 2010

Abstract

In this work, we study metal droplets on a semiconductor surface that are the initial stage for both droplet epitaxy and local droplet etching. The distributions of droplet geometrical parameters such as height, radius and volume help to understand the droplet formation that strongly influences subsequent nanohole etching. To investigate the etching and intermixing processes, we offer a new method of wetting angle analysis. The aspect ratio that is defined as the ratio of the height to radius was used as an estimation of wetting angle which depends on the droplet material. The investigation of the wetting angle and the estimation of indium content revealed significant materials intermixing during the deposition time. AFM measurements reveal the presence of two droplet groups that is in agreement with nanohole investigations. To explain this observation, we consider arsenic evaporation and consequent change in the initial substrate. On the basis of our analysis, we suggest the model of droplet evolution and the formation of two droplet groups.

Keywords:
Droplet epitaxy; Local droplet etching; Quantum dots; Atomic force microscopy; Molecular beam epitaxy