Graphene activating room-temperature ferromagnetic exchange in cobalt-doped ZnO dilute magnetic semiconductor quantum dots

Zhihu Sun, Xiaoyu Yang, Chao Wang, Tao Yao, Liang Cai, Wensheng Yan*, Yong Jiang, Fengchun Hu, Jingfu He, Zhiyun Pan, Qinghua Liu, Shiqiang Wei

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

43 Scopus citations

Abstract

Control over the magnetic interactions in dilute magnetic semiconductor quantum dots (DMSQDs) is a key issue to future development of nanometer-sized integrated "spintronic" 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 Zn0.98Co0.02O core turns the magnetic interactions from paramagnetic to ferromagnetic at room temperature, due to the hybridization of 2pz orbitals of graphene and 3d obitals of Co2+-oxygen-vacancy complexes. This design may open up a kind of possibility for manipulating the magnetism of doped oxide nanostructures.

Original languageEnglish (US)
Pages (from-to)10589-10596
Number of pages8
JournalACS Nano
Volume8
Issue number10
DOIs
StatePublished - Oct 28 2014

Bibliographical note

Publisher Copyright:
© 2014 American Chemical Society.

Keywords

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

ASJC Scopus subject areas

  • General Materials Science
  • General Engineering
  • General Physics and Astronomy

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