Fig. 1

Structural information for an as-drawn composite GaSb/Si fibre. Cross-sectional SEM images of the core; a BSE image, and b Si, c O, d Ga and e Sb EDX maps showing pseudo-eutectic microstructure (scale bar, 50 µm). f X-ray computed tomography image of the fibre (scale bar, 50 µm). g X-ray diffraction acquired with fibre rotating around its axis; inset is from a fibre with no core. h Relative Bragg intensities observed for silicon and GaSb planes in the composite fibres compared to powder spectra (count number for highest fibre XRD peak in parentheses), and i comparison of variation in intensities of the {220} Bragg peaks, during rotation, for a pure GaSb fibre (black), and the GaSb (orange) and silicon (blue) {220} reflections in the composite fibre. Pure GaSb fibres show many reflections, indicating polycrystallinity