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HL: Fachverband Halbleiterphysik

HL 48: Poster 2

HL 48.42: Poster

Donnerstag, 26. März 2009, 15:00–17:30, P2

Fabrication of nanoholes and rings by local droplet etching with In_xGa_1−x — •Andrea Stemmann, Christian Heyn, and Wolfgang Hansen — Institut für Angewandte Physik, Jungiusstr. 11C, 20355 Hamburg

We fabricate nanoholes and quantum rings on GaAs and AlGaAs surfaces by local droplet etching (LDE) with In_xGa_1−x. During the LDE process liquid metal droplets consisting of an In_xGa_1−x alloy are deposited on (001) GaAs at substrate temperatures ranging from 450 ^∘C to 540 ^∘C without an As flux. Subsequently, the samples are heated up to 600 ^∘C in the absence of As and the liquid material is removed. In this way deep nanoholes are formed at the position of the initial droplets. The nanohole openings are surrounded by walls which act as quantum rings with tuneable size and composition. The nanostructures are inspected with atomic force microscopy. The technique is compatible for in-situ overgrowth of the nanostructures with molecular beam epitaxy in order to fill the holes with optical active material and to cap the structures with barrier material. We find a strong dependence of hole density, depth, and diameter as well as of the wall structural properties on process temperature T and In content x. Interestingly, with increasing In content x the hole density is reduced up to a factor of 0.1. On the other hand, the hole and wall diameter and the hole depth strongly increase.