Synthesis, Structural and Magnetic Properties of Cobalt-Doped GaN Nanowires on Si by Atmospheric Pressure Chemical Vapor Deposition

Abstract

GaN nanowires (NWs) grown on silicon via atmospheric pressure chemical vapor deposition were doped with Cobalt (Co) by ion implantation, with a high dose concentration of 4 × 1016 cm−2, corresponding to an average atomic percentage of ~3.85%, and annealed after the implantation. Co-doped GaN showed optimum structural properties when annealed at 700 °C for 6 min in NH3 ambience. From scanning electron microscopy, X-ray diffraction, high resolution transmission electron microscope, and energy dispersive X-ray spectroscopy measurements and analyses, the single crystalline nature of Co-GaN NWs was identified. Slight expansion in the lattice constant of Co-GaN NWs due to the implantation-induced stress effect was observed, which was recovered by thermal annealing. Co-GaN NWs exhibited ferromagnetism as per the superconducting quantum interference device (SQUID) measurement. Hysteretic curves with Hc (coercivity) of 502.5 Oe at 5 K and 201.3 Oe at 300 K were obtained. Applied with a magnetic field of 100 Oe, the transition point between paramagnetic property and ferromagnetic property was determined at 332 K. Interesting structural and conducive magnetic properties show the potential of Co-doped GaN nanowires for the next optoelectronic, electronic, spintronic, sensing, optical, and related applications.

Magnetic properties of Mn-doped InSb nanowires from first principles

“…Since an experimental reports of T C reaching 200K in (Ga,Mn)As by patterning a heavily Mn-doped (Ga,Mn)As films into NWs [23], this success has inspired researchers to be interested in DMS NWs that takes advantage of the quantum size effect and surface effect of the NW. At the experimental level, the room temperature DMS NWs were developed using Mn-doped GaN NWs [24], Co-doped GaN NWs [25,26], Co-doped ZnO NWs [27], and (Cu,N)-codoped In 2 O 3 NWs [28]. Theoretically, Zhang et al suggested that the magnetic moment and the ferromagnetic states in (Ga,Mn)As NWs can be effectively regulated by the surface dangling bonds [29].…”