Investigation On The Electrical And Magnetic Properties Of Mo Doped In₂O₃ Films

Dilute magnetic semiconductors have been the frontier research objects in recent years because of the possibility of assembling charge and spin degrees of freedom in single substance. In2O3 based semiconductors will have good optoelectrical and magnetic properties by doping transition metals.There will be a great application prospect in the next generation of multi-function device due to integrating various semiconductor materials easily.In this research,Mo doped In2O3 diluted magnetic semiconductor bulks were prepared by high-temperature solid-state reaction method.And we briefly introduced the characteristics and principle of solid-state reaction.Then Mo-In2O3 diluted magnetic semiconductor thin films were grown on glass substrate by vacuum evaporation method. By changing the based temperature, evaporation time, evaporation atmosphere and Mo content,we acquired a series of film samples.The crystal structure,surface morphology,electrical transport properties,magnetic property and optical property were investigated by X-ray diffraction,scanning electron microscope, four probe resistance meter,Hall Effect tester,vibrating sample magnetometer and ultraviolet-visible light spectrophotometer. The conclusions are as follows.(1)Mo doped In2O3 bulks were prepared by high-temperature solid-state reaction method.Then Mo-In2O3 diluted magnetic semiconductor thin films were grown on glass substrate by vacuum evaporation method,and it behaved room-temperature ferromagnetion on the Mo concentration of 1%,2%,3%.(2)Structure and magnetic properties of the samples changed greatly on different Mo concentration.When the Mo concentration is 1%-3%,the crystal structure of the samples was the same with In2O3.But when the Mo concentration is 4%,there was the second phase In11Mo40O62precipitated.The lattice constant of the main phase of all the samples were less than that of In2O3 lattice constant,showing a decreasing trend. When the Mo concentration is 3%,we obtained the minimum lattice constant of 9.765A. Magnetic properties increased as the Mo concentration increased.When the Mo concentration is 3%,we obtained the best magnetic properties of 152emu/cm3.(3) The optimum technological parameters for the best physical properties of thin films were that the substrate temperature was 400℃, the argon oxygen flow ratio was 10/0,the evaporation time of 10min,the Mo content was 2%.Under the parameter, carrier concentration was -7.881×1019 cm-3; carrier mobility was 6.791 cm2/Vs, resistance was 0.003Ωcm,saturation magnetic moment was 108.232 emu/cm3,transmittance was 76%.(4) Mo on the mechanism of magnetic properties of In2O3.The ferromagnetion of Mo doped In2O3 thin films were intrinsic.The number of Mo6+ which replaced In3+ into the lattice determined the ferromagnetion.The electrons on d orbital would occurred exchange coupling interaction though the carriers.And a number of defects and oxygen vacancies in the film had a positive impact on the magnetic properties.(5) In the visible region,the transmittance of the films were more than 70%.