Doping catalysed unintentional hydrogenation effect on the structural, optical and magnetic properties of Co-doped ZnO semiconductor nanoparticles

Simultaneous Co (cobalt) doping and hydrogenation on wide band gap ZnO semiconductor nanoparticles was achieved via one pot chemical reduction. The powder X-ray diffraction results confirmed that the Co-doping induced hydrogenation did not change the wurtzite hexagonal ZnO structure for ZnCoO(H). The microscopic investigations displayed the formation of spherical ZnCoO(H) with loosely bounded nanoparticles. The X-ray photoelectron spectra strongly evidences the incorporation of Co and diffusion of H-2 into ZnO surface. From the photoluminescence spectra, it has been confirmed that the presence visible emission due to oxygen vacancy followed by Co2+ -induced fluorescent quenching in the visible region thus making the ZnO(H) and ZnCoO(H) materials for a tuneable optoelectronic applications like UV filter and blockers. The redshift in the energy bandgap due to sp-d interaction showed the successful replacement of Zn2+ ion by the dopant Co2+. The pure and Co-doped ZnO(H) showed an interesting magnetic behaviour in the M-H loop. As co-doping induced hydrogenation changes the magnetic property of ZnO to ferromagnetic nature which was mainly attributed to create oxygen vacancy (V-o) and hydrogenation-induced metal hydride couples (i.e. Zn-H, Co-H, and O-H). The proposed doping induced hydrogenation and their magneto-optic measurement can be applied for the design of next generation spintronic devices.

Automated summary

Simultaneous Co doping and hydrogenation on ZnO nanoparticles were achieved via chemical reduction. The results showed that the structure of ZnO did not change after Co doping and hydrogenation. The presence of visible emission due to oxygen vacancy and Co2+ induced fluorescent quenching was confirmed. The magnetic behavior of ZnO changed to ferromagnetic after Co doping and hydrogenation.