Computer analysis on the structure of low-density and high-density amorphous germanium

Kōga, Junichiro; Yonezawa, Fumiko; Nishio, Keiko; Yamaguchi, Toshio

doi:10.1016/j.jnoncrysol.2004.08.194

Cited by 4 publications

(1 citation statement)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There are also a number of theoretical examples of such a transition under high pressures from a low density amorphous (LDA) form based on tetrahedral units to a high density amorphous (HDA) form with larger coordination numbers than LDA. [30][31][32] The continuous random network (CRN) model, 11 which has been widely accepted for describing the structure of a-Si and a-Ge, is a typical LDA form. On the other hand, HDA forms involve larger coordination numbers than LDA forms and are similar to the b-Sn structure with the coordination 6 or liquid states with higher density than solids of the cubic diamond type structure.…”

Section: Discussionmentioning

confidence: 99%

Structural transition in sputter-deposited amorphous germanium films by aging at ambient temperature

Okugawa

Nakamura

Ishimaru

et al. 2016

Journal of Applied Physics

View full text Add to dashboard Cite

The structure of amorphous Ge (a-Ge) films prepared by sputter-deposition and the effects of aging at ambient temperature and pressure were studied by pair-distribution-function (PDF) analysis from electron scattering and molecular dynamics simulations. The PDFs of the as-deposited and aged samples for 3–13 months showed that the major peaks for Ge-Ge bonds decrease in intensity and broaden with aging for up to 7 months. In the PDFs of a-Ge of molecular dynamics simulation obtained by quenching liquid at different rates, the major peak intensities of a slowly cooled model are higher than those of a rapidly cooled model. Analyses on short- and medium-range configurations show that the slowly cooled model includes a certain amount of medium-range ordered (MRO) clusters, while the rapidly cooled model includes liquid-like configurations rather than MRO clusters. The similarity between experimental and computational PDFs implies that as-deposited films are similar in structure to the slowly cooled model, whereas the fully aged films are similar to the rapidly cooled model. It is assumed that as they undergo room-temperature aging, the MRO clusters disintegrate and transform into liquid-like regions in the same matrix. This transition in local configurations is discussed in terms of instability and the non-equilibrium of nanoclusters produced by a vapor-deposition process.

show abstract