J Phys Condens Matter. 2009 Oct 28;21(43):435501. doi: 10.1088/0953-8984/21/43/435501. Epub 2009 Oct 09.

Influence of Si and N additions on structure and phase stability of Ge(2)Sb(2)Te(5) thin films.

Journal of physics. Condensed matter : an Institute of Physics journal

Helmut Kölpin, Denis Music, Galyna Laptyeva, Reza Ghadimi, Florian Merget, Silvia Richter, Ruslàn Mykhaylonka, Joachim Mayer, Jochen M Schneider

PMID: 21832438 DOI: 10.1088/0953-8984/21/43/435501

Abstract

The influence of Si and N in Ge(2)Sb(2)Te(5) (space group [Formula: see text]) on structure and phase stability thereof was studied experimentally by thin film growth and characterization as well as theoretically by ab initio calculations. It was found that Si and N most probably accumulate in the amorphous matrix embedding Ge(2)Sb(2)Te(5) grains. The incorporation of Si and N in these samples causes an increase of the crystallization temperature and the formation of finer grains. N is more efficient in increasing the crystallization temperature and in reducing the grain size than Si which can be understood based on the bonding analysis. The incorporation of both Si and N in Ge(2)Sb(2)Te(5) is energetically unfavourable, leading to finer grains and larger crystallization temperatures. While in the case of Si additions no significant changes in bonding are observed, N additions appear to enable the formation of strong Te-N bonds in the amorphous matrix, which are shown to be almost twice as strong as the strongest bonds in unalloyed Ge(2)Sb(2)Te(5).

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• Journal Article