Magnetism Of High Concentration Co Doping On Zno Crystals By Hydrothermal Method

In this paper, the Zn1-xCoxO and Zn1-xCoxO:Sn crystals were synthesized by hydrothermal method, with mineralizer of 6mol/L KOH, fill factor of 70%, reaction temperature of 430℃.The precursor materials were high purity ZnO and high percentage transition metal oxide or chloride.The shape of high-quality Zn1-xCoxO and Zn1-xCoxO:Sn crystals is wurtzite structure by SEM. Length of Zn1-xCoxO crystals side is about 50μm, and Zn1-xCoxO crystals show that c-axis grow strongly. But length of Zn1-xCoxO crystals side is about 30μm, the rate of c-axis growth is restrained. Not only wurtzite ZnO but also Co3O4 are found in Zn1-xCoxO which were prepared by CoO and ZnO with the same an equal number of moles. And Zn1-xCoxO which were prepared by CoO and ZnO with the mole ratio 0.5∶1 are wurtzite ZnO. It is found that Co concentration are about 10at%( Co∶Zn=1∶1) 7at%(Co∶Zn=0.5∶1) and 12 at%(Sn∶Co∶Zn=0.02∶0.5∶1) by EDS. All of the crystals are paramagnetism.Zn1-xCoxO:Sn crystals are fabricated on ZnO seed plate using hydrothermal method. The ZnO seed plate have black green films which are wurtzite ZnO. The results show Co concentration is about 8at% in films, and the films exhibit a paramagnetism behavior. Semiconducting behavior with n-type carriers was confirmed by hall-effect measurements.