Institute for Solid State Physics, Jena University, Max-Wien-Platz 1, 07743 Jena, Germany.
Nano Lett. 2011 Sep 14;11(9):3935-40. doi: 10.1021/nl2021653. Epub 2011 Aug 22.
We report on highly Mn-doped GaAs nanowires (NWs) of high crystalline quality fabricated by ion beam implantation, a technique that allows doping concentrations beyond the equilibrium solubility limit. We studied two approaches for the preparation of Mn-doped GaAs NWs: First, ion implantation at room temperature with subsequent annealing resulted in polycrystalline NWs and phase segregation of MnAs and GaAs. The second approach was ion implantation at elevated temperatures. In this case, the single-crystallinity of the GaAs NWs was maintained, and crystalline, highly Mn-doped GaAs NWs were obtained. The electrical resistance of such NWs dropped with increasing temperature (activation energy about 70 meV). Corresponding magnetoresistance measurements showed a decrease at low temperatures, indicating paramagnetism. Our findings suggest possibilities for future applications where dense arrays of GaMnAs nanowires may be used as a new kind of magnetic material system.
我们报告了通过离子注入技术制备的高结晶质量的高 Mn 掺杂 GaAs 纳米线（NWs），该技术允许掺杂浓度超过平衡溶解度极限。我们研究了两种制备 Mn 掺杂 GaAs NWs 的方法：首先，室温下的离子注入随后进行退火导致多晶 NWs 和 MnAs 和 GaAs 的相分离。第二种方法是在高温下进行离子注入。在这种情况下，GaAs NWs 的单晶性得以保持，并获得了结晶性、高 Mn 掺杂 GaAs NWs。这种 NWs 的电阻随温度升高而降低（激活能约为 70meV）。相应的磁阻测量表明，低温下电阻减小，表明存在顺磁性。我们的发现为未来的应用提供了可能性，其中密集排列的 GaMnAs 纳米线可能用作新型磁性材料系统。
