State Key Laboratory of Precision Measuring Technology & Instruments, Centre of MicroNano Manufacturing Technology, Tianjin University, Tianjin 300072, China.
Nanoscale Res Lett. 2013 Aug 15;8(1):353. doi: 10.1186/1556-276X-8-353.
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.
采用分子动力学模拟研究了单晶锗的纳米压痕。研究了不同晶向的相变路径和转变区域的分布。结果表明单晶锗具有各向异性。在（010）晶面压痕时，在工具下的亚表面区域发现了由金刚石立方结构向β-锡-锗的纳米压痕诱导相变，而当锗沿[101]和[111]方向加载时，在压头正下方的区域观察到直接非晶化。转变相沿锗的<110>滑移方向延伸。根据压痕平面的晶体取向，卸载后变形层的深度和形状有很大的不同。研究结果表明，相变是单晶锗薄膜在纳米压痕中变形的主要机制。
