CNR-Istituto dei Sistemi Complessi, U.O.S. di Tor Vergata , Via del Fosso del Cavaliere 100, 00133 Roma, Italy.
Laboratori Nazionali di Frascati, INFN , Via E. Fermi 27, Frascati, RM 00044, Italy.
ACS Appl Mater Interfaces. 2016 May 25;8(20):12925-31. doi: 10.1021/acsami.6b04203. Epub 2016 May 11.
Impressive changes in the transport and ferromagnetic properties of Co-doped ZnO thin films have been obtained by postgrowth hydrogen irradiation at temperatures of 400 °C. Hydrogen incorporation increases the saturation magnetization by one order of magnitude (up to ∼1.50 μB/Co) and increases the carrier density and mobility by about a factor of two. In addition to the magnetic characterization, the transport and structural properties of hydrogenated ZnO:Co have been investigated by Hall effect, local probe conductivity measurements, micro-Raman, and X-ray absorption spectroscopy. Particular care has been given to the detection of Co oxides and metal Co nanophases, whose influence on the increase in the transport and ferromagnetic properties can be excluded on the ground of the achieved results. The enhancement in ferromagnetism is directly related to the dose of H introduced in the samples. On the contrary, despite the shallow donor character of H atoms, the increase in carrier density n is not related to the H dose. These apparently contradictory effects of H are fully accounted for by a mechanism based on a theoretical model involving Co-VO (Co-O vacancy) pairs.
通过在 400°C 温度下进行后生长氢辐照，在 Co 掺杂 ZnO 薄膜的输运和铁磁性能方面获得了显著的变化。氢的掺入使饱和磁化强度提高了一个数量级（高达约 1.50μB/Co），并使载流子密度和迁移率提高了约两倍。除了磁特性外，还通过 Hall 效应、局部探针电导率测量、微拉曼和 X 射线吸收光谱研究了氢化 ZnO:Co 的输运和结构特性。特别注意了 Co 氧化物和 Co 纳米相的检测，根据所得到的结果，可以排除它们对输运和铁磁性能增加的影响。铁磁性的增强与样品中引入的 H 剂量直接相关。相反，尽管 H 原子具有浅施主特性，但载流子密度 n 的增加与 H 剂量无关。这些看似矛盾的 H 效应可以通过一个基于涉及 Co-VO（Co-O 空位）对的理论模型的机制来充分解释。
