Growth And Properties Of Diluted Magnetic-doped In₂O₃ Nanowires

Dilute magnetic semiconductors (DMSs) simultaneously manipulate the degrees of freedom of both the charge and spin of electrons in a single device, which has the potential to revolutionize electronic devices. In some aspects, the envisioned spintronic devices often mirror or even surpass their counterparts in conventional semiconductor electronics. The main purpose of our study is prepare diluted magnetic semiconductors with excellent properties. In2O3 is a wide-band-gap semiconductor material, the direct bandgap at room temperature is 3.75eV, it has been widely used due to its unique optical, chemical and electrical properties. In2O3 doped with the transition-metal elements may exhibit magnetism and the transition-metal elements can be easily doped into the In2O3 material. Therefore, In2O3-based diluted magnetic semiconductor is an hotspot of spin semiconductor research.In this letter, Nd-doped and Fe doped In23 diluted magnetic semiconductor nanowires were successfully grown by the chemical vapor deposition (CVD) technique. The structure and magnetic properties of Nd-doped and Fe doped In2O3 diluted magnetic semiconductor nanowires were studied by Scanning Electron Microscopy (SEM), Transmission Electron Microscope (TEM), X-ray Photoelectron Spectroscopy (XPS), X-Ray Diffraction (XRD), Raman Spectrue (RAMAN), Superconducting Quantum Interference Device (SQUID), Vibrating Sample Magnetometer (VSM), photoluminescence (PL) and so on. The main contents are following:We firstly fabricated Nd-doped In2O3 nanowires by an Au-catalyzed chemical vapor deposition (CVD) method; The high-resolution transmission electron microscopy (HRTEM) image shows that our samples possess excellent crystallinity; The fast Fourier transform (FFT) pattern of the HRTEM image confirm that the Nd-doped In2O3 nanowires can be indexed as the expected cubic bixbyite structure; EDS, XPS, RAMAN show that 1.1 at.% Nd was doped into In2O3 nanowires without any ferromagnetic metallic impurities and the valence state of Nd are +3; Calculating implies that oxygen vacancies (Vo) exist in Nd-doped In2O3 nanowires; the XRD patterns of the Nd-doped In2O3 nanowires show the cubic bixbyite structure of In2O3 without any secondary phase; We obverted robust RTFM in the In2O3 nanowires induced by the Nd doping, experiments show that the observed RTFM does not come from any experimental artifacts/contaminations. We suggest that the origin of the ferromagnetism is attributed to the long-range-mediated magnetization among Nd3+-vacancy complexes through percolation-bound magnetic polarons.We also fabricated Nd-doped In2O3 nanowires by an Au-catalyzed chemical vapor deposition (CVD) method; EDX, RAMAN that 2.3at.% Fe was doped into In2O3 nanowires and the relatively uniform distribution of Fe in samples; XPS show that Fe indeed exists in In2O3 as a mixture of Fe2+ and Fe3+; We also obverted robust RTFM in the In2O3 nanowires induced by the Fe doping, experiments show that the observed RTFM does not come from any experimental artifacts/contaminations. After annealing, Ms and coercive fields of Fe-doped In2O3 decrease, the origin of room-temperature ferromagnetism in Fe-doped In2O3 nanowires is explained by the bound magnetic polaron model.