Thermally pressure-induced partial structural phase transitions in core–shell InSb-SiO 2 nanoballs/microballs: characterization, size and interface effect

Core–shell InSb-SiO 2 nanoballs/microballs were synthesized on a Si substrate by carbonthermal reactions at a temperature of 900 °C. High-resolution transmission microscopy (HRTEM) images revealed that the surfaces of the InSb nanoballs/microballs were covered by amorphous SiO 2 layers. On the basis of our theoretical calculation, the thermal expansion coefficient (TEC) of the InSb crystals is ten times higher than that of the SiO 2 shell. Therefore, the SiO 2 serves as a constraining shell for the InSb core so that the compressive stress of ∼−94 MPa can accumulate in the InSb core while a tensile stress of 196 MPa forms in the SiO 2 shell. The thermal excitation accumulated compressive stress in the InSb core, causing a partial structural phase transition from a cubic zinc-blende structure to a hexagonal wurtzite structure. Many lattice defects, such as stacking faults and Moiré fringes, have been observed on the surface of the I...

Jyh Ming Wu, Hsiao Jung Huang and Ying Hong Lin

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