Origin of magnetic properties in carbon implanted ZnO nanowires

• Published in: Scientific reports Vol. 8; no. 1; pp. 7758 - 13
• Main Authors: Wang, Y. F., Shao, Y. C., Hsieh, S. H., Chang, Y. K., Yeh, P. H., Hsueh, H. C., Chiou, J. W., Wang, H. T., Ray, S. C., Tsai, H. M., Pao, C. W., Chen, C. H., Lin, H. J., Lee, J. F., Wu, C. T., Wu, J. J., Chang, Y. M., Asokan, K., Chae, K. H., Ohigashi, T., Takagi, Y., Yokoyama, T., Kosugi, N., Pong, W. F.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 17.05.2018; Nature Publishing Group
• Subjects: 140/146; 639/301; 639/925/357; Circular dichroism; Humanities and Social Sciences; Magnetic properties; Microscopes; multidisciplinary; Nanotechnology; Photons; Science; Science (multidisciplinary)
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-018-25948-x

Various synchrotron radiation-based spectroscopic and microscopic techniques are used to elucidate the room-temperature ferromagnetism of carbon-doped ZnO-nanowires (ZnO-C:NW) via a mild C + ion implantation method. The photoluminescence and magnetic hysteresis loops reveal that the implantation of C reduces the number of intrinsic surface defects and increases the saturated magnetization of ZnO-NW. The interstitial implanted C ions constitute the majority of defects in ZnO-C:NW as confirmed by the X-ray absorption spectroscopic studies. The X-ray magnetic circular dichroism spectra of O and C K -edge respectively indicate there is a reduction in the number of unpaired/dangling O 2 p bonds in the surface region of ZnO-C:NW and the C 2 p -derived states of the implanted C ions strongly affect the net spin polarization in the surface and bulk regions of ZnO-C:NW. Furthermore, these findings corroborate well with the first-principles calculations of C-implanted ZnO in surface and bulk regions, which highlight the stability of implanted C for the suppression and enhancement of the ferromagnetism of the ZnO-C:NW in the surface region and bulk phase, respectively.