A silicon microwire under a three-dimensional anisotropic tensile stress

Xiaoyu Ji, Nicolas Poilvert, Wenjun Liu, Yihuang Xiong, Hiu Yan Cheng, John V. Badding, Ismaila Dabo, Venkatraman Gopalan

Research output: Contribution to journalArticlepeer-review


Three-dimensional tensile stress, or triaxial tensile stress, is difficult to achieve in a material. We present the investigation of an unusual three-dimensional anisotropic tensile stress field and its influence on the electronic properties of a single crystal silicon microwire. The microwire was created by laser heating an amorphous silicon wire deposited in a 1.7 μm silica glass capillary by high pressure chemical vapor deposition. Tensile strain arises due to the thermal expansion mismatch between silicon and silica. Synchrotron X-ray micro-beam Laue diffraction (μ-Laue) microscopy reveals that the three principal strain components are +0.47% (corresponding to a tensile stress of +0.7 GPa) along the fiber axis and nearly isotropic +0.02% (corresponding to a tensile stress of +0.3 GPa) in the cross-sectional plane. This effect was accompanied with a reduction of 30 meV in the band gap energy of silicon, as predicted by the density-functional theory calculations and in close agreement with energy-dependent photoconductivity measurements. While silicon has been explored under many stress states, this study explores a stress state where all three principal stress components are tensile. Given the technological importance of silicon, the influence of such an unusual stress state on its electronic properties is of fundamental interest.

Original languageEnglish (US)
Article number091911
JournalApplied Physics Letters
Issue number9
StatePublished - Feb 27 2017

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)


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