Open Access Nano Express

Nanoindentation-induced phase transformation and structural deformation of monocrystalline germanium: a molecular dynamics simulation investigation

Min Lai, Xiaodong Zhang* and Fengzhou Fang

Author Affiliations

State Key Laboratory of Precision Measuring Technology & Instruments, Centre of MicroNano Manufacturing Technology, Tianjin University, Tianjin 300072, China

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Nanoscale Research Letters 2013, 8:353  doi:10.1186/1556-276X-8-353

Published: 15 August 2013

Abstract

Molecular dynamics simulations were conducted to study the nanoindentation of monocrystalline germanium. The path of phase transformation and distribution of transformed region on different crystallographic orientations were investigated. The results indicate the anisotropic behavior of monocrystalline germanium. The nanoindentation-induced phase transformation from diamond cubic structure to β-tin-Ge was found in the subsurface region beneath the tool when indented on the (010) plane, while direct amorphization was observed in the region right under the indenter when the germanium was loaded along the [101] and [111] directions. The transformed phases extend along the < 110 > slip direction of germanium. The depth and shape of the deformed layers after unloading are quite different according to the crystal orientation of the indentation plane. The study results suggest that phase transformation is the dominant mechanism of deformation of monocrystalline germanium film in nanoindentation.

Keywords:
Monocrystalline germanium; Nanoindentation; Phase transformation; Anisotropy; Molecular dynamics simulation