Au-catalyzed synthesis and characterisation of phase change Ge-doped SbaTe nanowires by MOCVD

• Published in: Journal of crystal growth 2013-05, Vol.370, p.323-327
• Main Authors: Longo, M, Stoycheva, T, Fallica, R, Wiemer, C, Lazzarini, L, Rotunno, E
• Format: Article
• Language: English
• Subjects: Germanium
• ISSN: 0022-0248
• DOI: 10.1016/j.jcrysgro.2012.09.021

The interest in the Ge doped SbaTe chalcogenide alloy is mainly related to phase change memory applications. In view of phase change device scaling and reduction of programming energy, SbaTe nanowires (NWs) become an attractive option. In this work, in order to investigate their potential transferability to industrial implementation, the self-assembly of Sb2Te3 NWs and GeaSbaTe NWs with Ge content in the range of 1a13% (Ge doping) was studied by coupling the advantages of MOCVD and the VapouraLiquidaSolid (VLS) mechanism. The results show the structural and compositional gradual changes occurring from pure Sb2Te3 NWs to the previously reported, stoichiometric Ge1Sb2Te4 NWs [[12] M. Longo et al., Nano Lett., 12 (2012) 1509]. The typical diameter of the obtained NWs resulted to be 50 nm, with lengths up to 3 mu m. The typology of Au catalyst nanoislands influenced both the NW morphology and the Ge incorporation during the VLS self-assembly; the Ge metalorganic precursor partial pressure affected the NW morphology and their structure. Finally, TEM observations revealed that defect-free, monocrystalline Sb2Te3 and Ge-doped SbaTe phase change NWs could be obtained.