Characterization of Thermal Conductivity in Fe-ions Irradiated Single Crystal Silicon
Thermal conductivity degrades after materials exposed to irradiation that causes microstructural damages. Silicon is widely used in integrated circuits, microchips and solar panels on the International Space Station. Its thermal conductivity is expected to be heavily influenced by the natural radiation in space. In this study, thermal conductivity of silicon samples, irradiated with energetic Fe ions (3.4 MeV) at room temperature with the doses of 1×10^14 ions/cm2, 1×10^15 ions/cm2 and 1×10^16 ions/cm2, respectively, were measured. The peak dpa (displacement-per-atom) of three samples is 0.18, 1.8, and 18, respectively, with the damaged depth of ~3.4 µm. Modulated thermoreflectance technique was employed for experimental data acquisition. The degradation of thermal conductivity along the depth direction in graded damaged silicon samples was quantified from a multi-layer model. A 70 % and 89 % degradation of thermal conductivity was observed in the samples irradiated at the dose of 1×10^14 ions/cm2 and 1×10^15 ions/cm2, with the corresponding dpa 0.055 and 0.55, respectively. The sample irradiated at the dose of 1×10^16 ions/cm2 has completed the crystalline-to-amorphous transition, and an over 96% reduction of thermal conductivity was observed with a value of 3.73 W·m-1·K-1. A better understanding of the contributions of defects, produced by displacement cascades in irradiation, to thermal conductivity is possible with further electron microscopy characterization.
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YUEFANG DONG (POC,Primary Presenter,Author), Utah State University, firstname.lastname@example.org;
Zilong Hua (Co-Author), Utah State University, email@example.com;
Heng Ban (Author,Co-Author), Utah State University, firstname.lastname@example.org;