Fe-doped β-Rhombohedral boron: Structural changes at the p-type/n-type transition

• We measured the spectra of IR- and Raman-active phonons of Fe-doped β-rhombohedral boron.
• The phonon frequencies vary monotonically within the p-type and the n-type regions respectively.
• Discontinuities of phonon frequencies occur at the p-type/n-type transition indicating structural changes.
• Fe-induced structural changes are restricted to its structural elements, while the basic structure remains largely unchanged.

n-type β-rhombohedral boron is e.g. obtained by interstitial doping with Fe atoms exceeding 2.45 at.%. The spectra of Raman- and IR-active phonons have been measured up to the solubility limit of ∼4 at.%. Numerous significant discontinuities in the spectra indicate structural changes at the p/n-transition. These might be restricted to specific elements of the structure, as the lattice parameters vary continuously, thus indicating that the overall structure remains largely unchanged.

Parameters of Raman-active phonon vs. Fe content.Figure optionsDownload as PowerPoint slide