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A highly unconventional growth scenario is reported upon deposition of GeTe films on the hydrogen passivated Si (111) surface. Initially, an amorphous film forms for growth parameters that should yield a crystalline material. The entire amorphous film then crystallizes once a critical thickness of four GeTe bilayers is reached, subsequently following the GeTe (111)|| Si (111): GeTe [− 110]|| Si [− 110] epitaxial relationship rigorously. Hence, in striking contrast to conventional lattice-matched epitaxial systems, a drastic improvement in atomic order is observed above a critical film thickness. Raman spectra show a remarkable change of vibrational modes above the critical thickness that is attributed to a change in the nature of the bonds: While ordinary covalent bonding is found in ultrathin films, resonant bonding can prevail only once a critical thickness is reached. This scenario is further supported by density functional …
Nature Publishing Group
Publication date: 
1 Jun 2017

Ruining Wang, Wei Zhang, Jamo Momand, Ider Ronneberger, Jos E Boschker, Riccardo Mazzarello, Bart J Kooi, Henning Riechert, Matthias Wuttig, Raffaella Calarco

Biblio References: 
Volume: 9 Issue: 6 Pages: e396-e396
NPG Asia Materials