Size-dependent phase transformations during point loading of silicon

2019-11-09 03:07:01

phase size contact silicon situ

责任者: Mann, A.B.;van Heerden, D.;Pethica, J.B.;Weihs, T.P. 单位: Dept. of Mater. Sci. & Eng., Johns Hopkins Univ., Baltimore, MD, USA 来源出处: Journal of Materials Research(J. Mater. Res. (USA)),2000/08/,15(8):1754-8 摘要: Using a unique combination of in situ electrical and acoustical measurements and ex situ transmission electron microscopy, the phase transformations of silicon during point loading were shown to exhibit a strong dependence on the size of the deformed volume. For nanometer-size volumes of silicon, the final phase was the body centered cubic structure BC8, but for larger volumes it was amorphous. The size dependence was explained by considering how shear stress fields vary with contact size and how interfacial effects between the silicon substrate and the BC8 phase determine its stability. For both small and large contacts the presence of a nonmetallic phase (assumed to be the rhombohedral structure R8) was observed 关键词: acoustic emission;amorphisation;contact resistance;elemental semiconductors;high-pressure solid-state phase transformations;indentation;shear deformation;silicon;transmission electron microscopy;size-dependent phase transformations;point loading;deformed volume size;nanometer-size volumes;body centered cubic structure;amorphous phase;shear stress fields;contact size;interfacial effects;BC8 phase;phase stability;nonmetallic phase;rhombohedral structure;ex situ TEM;in situ electrical measurements;in situ acoustical measurements;high-pressure phases;nanoscale contacts;contact resistance;rectification;acoustic emission;indentation;amorphisation;Si