Graphene Activating Room-Temperature Ferromagnetic Exchange in Cobalt-Doped ZnO Dilute Magnetic Semiconductor Quantum Dots

详细信息    查看全文

• 作者：Zhihu Sun ; Xiaoyu Yang ; Chao Wang ; Tao Yao ; Liang Cai ; Wensheng Yan ; Yong Jiang ; Fengchun Hu ; Jingfu He ; Zhiyun Pan ; Qinghua Liu ; Shiqiang Wei
• 刊名：ACS Nano
• 出版年：2014
• 出版时间：October 28, 2014
• 年：2014
• 卷：8
• 期：10
• 页码：10589-10596
• 全文大小：573K
• ISSN：1936-086X

文摘

Control over the magnetic interactions in dilute magnetic semiconductor quantum dots (DMSQDs) is a key issue to future development of nanometer-sized integrated 鈥渟pintronic鈥?devices. However, manipulating the magnetic coupling between impurity ions in DMSQDs remains a great challenge because of the intrinsic quantum confinement effects and self-purification of the quantum dots. Here, we propose a hybrid structure to achieve room-temperature ferromagnetic interactions in DMSQDs, via engineering the density and nature of the energy states at the Fermi level. This idea has been applied to Co-doped ZnO DMSQDs where the growth of a reduced graphene oxide shell around the Zn_0.98Co_0.02O core turns the magnetic interactions from paramagnetic to ferromagnetic at room temperature, due to the hybridization of 2p_z orbitals of graphene and 3d obitals of Co²⁺鈥搊xygen-vacancy complexes. This design may open up a kind of possibility for manipulating the magnetism of doped oxide nanostructures.

Keywords:

Co-doped ZnO QDs; XAFS; RGO; ferromagnetic exchange