Berlin 2012 – scientific programme
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KR: Fachgruppe Kristallographie
KR 10: Crystallography in Nanoscience
KR 10.6: Talk
Thursday, March 29, 2012, 11:20–11:40, E 124
Manipulation of Ge quantum dot ordering in alumina matrix by deposition conditions — •Maja Buljan1, Carsten Baehtz2, Václav Holý3, Nikola Radić1, Olga Roshchupkina2, Slawomir Prucnal2, Arndt Muecklich2, Václav Valeš3, Sigrid Bernstorff4, and Joerg Grenzer2 — 1Ruder Bošković Institute, Croatia — 2Helmholtz Zentrum Dresden Rossendorf, Gremany — 3Charles University in Prague, Czech Republic — 4Sincrotrone Trieste, Italy
We present an investigation of ordering and PL properties of Ge QDs in an alumina matrix formed by magnetron-sputtering deposition of (Ge+Al2O3)/Al2O3 multilayers. The self-assembly process occurs during the deposition and results with the formation of three-dimensional quantum dots lattices. We investigate the dependencies of the size and ordering properties on the deposition temperature, rotation of the substrate holder and direction of the incoming flux of Ge during the deposition process. The results of the investigation show that tuning the deposition temperature enables manipulation with QD sizes and their mutual distances. We show that the ordering of QDs obtained by deposition on fixed substrate holder leads to the formation of a quantum dot crystal, while the rotation of substrate holder leads to randomly rotated domains with regular ordering. The observed phenomenon is explained by a combination of the surface morphology effect on the nucleation positions of Ge quantum dots with a lateral inhomogeneity of the ad-atom flux. In addition, we show that the resulting quantum-dot lattices have size-dependent PL properties.