Synthesis of diluted magnetic semiconductor Bi2−xMnxTe3 nanocrystals in a host glass matrix

Abstract

Diluted magnetic semiconductors of manganese doped in bismuth-telluride nanocrystals (Bi2−xMnxTe3 NCs) were grown in a glass matrix and investigated by Transmission Electron Microscopy, X-Ray Diffraction, Atomic Force Microscopy/Magnetic Force Microscopy, and Electron Paramagnetic Resonance. TEM images showed that the nanocrystals formed within the glass matrix were nearly spherical, with average sizes between 4 and 5 nm, and d015-spacing of approximately 0.322 nm, which corresponds to the (015) interplanar distance in Bi2Te3 bulk. The diffraction patterns showed that the diffraction peak associated with the (015) plane of the Bi2−xMnxTe3 nanocrystals shifts to larger diffraction angles as manganese (Mn) concentration increases, suggesting that the Mn2+ ions are substitutional defects occupying Bi sites (MnBi). AFM and MFM measurements showed magnetic phase contrast patterns, providing further evidence of Mn2+ ion incorporation in the nanocrystal structure. EPR signal of manganese ion incorporation and valence states in the crystalline structure of the Bi2Te3 nanocrystals confirmed the presence of the Mn2+ state.