Mechanical properties of hydrogenated amorphous silicon (a-Si:H) particles
TZ Jiang and F Khabaz and A Marne and CL Wu and R Gearba and R Bodepudi and RT Bonnecaze and KM Liechti and BA Korgel, JOURNAL OF APPLIED PHYSICS, 126, 204303 (2019).
A nanoindenter was used to compress individual particles of hydrogenated amorphous silicon (a-Si:H) ranging in diameter from 290 nm to 780 nm. The colloidal synthesis used to produce the particles enables the hydrogen content to be manipulated over a wide range, from about 5 at. % to 50 at. %, making these a-Si:H particles promising for applications in lithium ion batteries, hydrogen storage, and optical metamaterials. Force-displacement curves generated using a tungsten probe flattened with focused ion beam exhibited elastic and then plastic deformations, followed by fracture and crushing of the particles. For particles with 5% and 50% H, Young's moduli, yield strengths, and compressive strengths were 73.5(+/- 19.5) GPa, 5.8 GPa, and 3.2(+/- 0.1)-9.3(+/- 0.6) GPa and 31.2(+/- 9.0) GPa, 2.5 GPa, and 1.8 (+/- 0.3)-5.3 (+/- 0.8) GPa, respectively. Particles with more hydrogen were significantly more compliant and weaker. This is consistent with atomistically detailed molecular dynamics simulations, which revealed compression forms of an interphase of H atom clusters that weakens the material. Published under license by AIP Publishing.
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