Open Access Nano Express

Relationship between structural changes, hydrogen content and annealing in stacks of ultrathin Si/Ge amorphous layers

Cesare Frigeri1*, Miklós Serényi2, Nguyen Quoc Khánh2, Attila Csik3, Ferenc Riesz2, Zoltán Erdélyi4, Lucia Nasi1, Dezső László Beke4 and Hans-Gerd Boyen5

Author Affiliations

1 CNR-IMEM Institute, Parco Area delle Scienze 37/A, 43100 Parma, Italy

2 Research Institute for Technical Physics and Materials Science, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary

3 Institute of Nuclear Research of the Hungarian Academy of Sciences, P.O. Box 51, H-4001 Debrecen, Hungary

4 Department of Solid State Physics, University of Debrecen, P.O. Box 2, H-4010 Debrecen, Hungary

5 Institute for Materials Research (IMO), Hasselt University, Diepenbeek, Belgium

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Nanoscale Research Letters 2011, 6:189  doi:10.1186/1556-276X-6-189

Published: 1 March 2011

Abstract

Hydrogenated multilayers (MLs) of a-Si/a-Ge have been analysed to establish the reasons of H release during annealing that has been seen to bring about structural modifications even up to well-detectable surface degradation. Analyses carried out on single layers of a-Si and a-Ge show that H is released from its bond to the host lattice atom and that it escapes from the layer much more efficiently in a-Ge than in a-Si because of the smaller binding energy of the H-Ge bond and probably of a greater weakness of the Ge lattice. This should support the previous hypothesis that the structural degradation of a-Si/a-Ge MLs primary starts with the formation of H bubbles in the Ge layers.