Study On Electrical And Magnetic Properties Of Dilute Magnetic Semiconductor Based On ZnO

Spintronic devices have the advantages of small size,low energy consumption,fast speed and non-volatility.Diluted magnetic semiconductors have both magnetic and semiconductor properties.Theoretically,it is predicted that the Curie temperature of ZnO-based magnetic semiconductors can reach above room temperature,Meanwhile,ZnO has the advantages of stable physical and chemical properties,abundant raw materials,low toxicity and inexpensive price.Therefore,ZnO-based magnetic semiconductors have attracted wide attention.In this paper,the samples of Al³⁺implanted in Zn_1-x-x Co_xO were prepared by solid state method and ion implantation method.The crystal structure,room temperature ferromagnetism and electrical properties of the samples were studied.?1?Zn_1-xCo_xO?_x=0.01,0.02,0.03,0.05?samples were prepared by solid-state reaction at different sintering temperature?T=1000?,1100?,1200?,1300??.The results of XRD show that Co²⁺was introduced into ZnO lattice,and the position of Zn²⁺was successfully substituted.There was no Co single oxide and Co oxide.All the samples were hexagonal wurtzite structure.The samples whose sintering temperature is 1200?and doping concentration is 3%have the best crystallinity.The magnetic properties of the samples were measured by VSM at room temperature,and the results show ferromagnetism.With the increase of Co²⁺concentration,the ferromagnetism is enhanced.The ferromagnetism of samples sintered at 1200?is the weakest.Because Co²⁺is more evenly distributed in the sample and the crystallinity is the best.?2?Zn_1-xCo_xO samples were prepared by solid-state reaction method.Al³⁺was implanted by ion implantation.XRD results show that all the samples are hexagonal wurtzite structure,which indicates that Co²⁺doped by solid-state reaction and Al³⁺from ion implantation did not change the ZnO structure.The samples whose sintering temperature is1200?and doping concentration is 3%have the sharpest diffraction peak and the best crystallinity.The magnetic properties of the samples were measured by VSM at room temperature.Al³⁺has weak effect on the paramagnetism.The electrical properties of the samples were measured by Hall effect meter.The results show that Co²⁺has little effect on the electrical properties.With the increase of Al³⁺implantation rate,the mobility increase and carrier concentration is lower,which indicates that Al³⁺greatly improve the electrical properties;The electrical characteristics of the samples?optimum sintering temperature T=1200??are as follows:the resistivity is 15⁵0?·cm,the carrier concentration is 10¹⁴¹0¹⁵/cm³ and the mobility is about several hundred or even one thousand.