Highly Mn-doped GaAs nanowires and their transport properties

Diluted magnetic semiconductors exhibit unique magnetic and electrical transport properties which arise from the coupling of carrier spins and localized moments. Dilute magnetic semiconductors can be achieved by incorporating transition metal impurities in III-V semiconductor materials, for example Mn in GaAs. However, due to the low solubility limits, sufficient Mn concentrations can only be achieved by non-equilibrium growth methods. Self-organized growth of GaAs nanowires requires high temperatures, which inhibit incorporation of sufficient Mn during growth of GaAs nanowires or lead to segregation of MnAs clusters. Post-growth doping via ion implantation allows incorporation beyond solubility limits. However, ion implantation causes a lot of defects and partial amorphization of the target material, which makes subsequent annealing a necessity. I will discuss the fabrication of highly Mn doped, single-crystalline GaAs nanowires by ion implantation at elevated temperature to facilitate in situ dynamic annealing. Transport properties of GaAs:Mn nanowires under varying temperature and magnetic field conditions will be discussed.