Regensburg 2013 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 41: Quantum dots and wires: Preparation and characterization
HL 41.2: Vortrag
Dienstag, 12. März 2013, 11:30–11:45, H15
Different Approaches for Uncovering InAs/AlAs Quantum Dots — •Evgeniya Sheremet1, Raul D. Rodriguez1, Torsten Jagemann2, Wolfgang Grünewald3, Doreen Dentel2, Alexander Toropov4, Alexander Milekhin4, and Dietrich R.T. Zahn1 — 1Semiconductor Physics, Chemnitz University of Technology, D-09107 Chemnitz, Germany — 2Solid Surfaces Analysis, Chemnitz University of Technology, D-09107 Chemnitz, Germany — 3Leica Mikrosysteme GmbH, 1170 Vienna, Austria — 4Institute of Semiconductor Physics, 630090 Novosibirsk, Russia
The versatile capability of tuning energy band-gap by changing size, and composition makes quantum dot (QD) materials of significant technological impact. In this work, towards the study of electronic, structural and vibrational properties of a single QD, we performed experimental investigations of InAs (AlAs) QD in AlAs (InAs) matrix prepared by molecular beam epitaxy on GaAs substrates. We report on the systematic investigation of different surface preparation methods including crystal cleavage, ion milling, and mechanical polishing and their effect on the QD superlattice topography. We found that the less invasive sample processing method, namely crystal cleavage, provides very good surface structure but fails for the structures with growth defects. In this case the most optimal QD surface is achieved by ion milling at low temperature and low ion energy, what is revealed by atomic force microscopy. The structural defects introduced by preparation on QD superlattices, as well as degradation over time were investigated using Raman spectroscopy.