Structural And Physical Properties Of Minor Magnetic Elements Doped Te-Based And Se-Based Semiconductor Materials

Diluted magnetic semiconductor have the characteristics of semiconductors and magnetic materials.It's excellent magnetic properties,magneto optical properties magnetic and magnetoelectric properties,diluted magnetic semiconductors have attracted widespread attention.CuIn1-xMxTe2(M=Mn,Co,x=0-0.3),CuIn1-xCoxSe2(x=0-0.3),and Cu1-xCoxInTe2 compounds(x=0-0.3)were prepared using arc melting in an atmosphere of high purity argon gas.Then the compounds were annealed to eliminate the residual stress and metastable phase.Powder X-ray diffractometer(XRD),TREOR indice,rietveld structure refinement technology,scanning electron microscope(SEM),energye disperse spectrum(EDS),vibrating sample magnetometer(VSM),superconducting quantum interference Device(SQUID),ultraviolet and visible spectrophotometer(UV-Vis),stand four-probe method and differential thermal analyzer used to investigate the structure and physical properities of the alloys.The results reveal that the main phase of CuIn1-xMxTe2,CuIn1-xCoxSe2 and Cu1-xCoxInTe2 is CuInTe2 with a group of I-42d.For CuIn1-xMxTe2 and CuIn1-xCoxSe2,the atomic occupations in one unit cell are responding to the 4a(0,0,0)for Cu atoms,the 4b(0,0,1/2)for In and M atoms,the 8d(x,1/4,1/8)site for Te or Se atoms.For Cu1-xCoxInTe2 the 4a(0,0,0)is occupied by Cu and Co atoms.By using scanning electron microscope(SEM),we can conclude that the Co doping into Cu1-xCoxInTe2 can lead to a gradual decrease in the crystal particles,which are separated from the bulk.At room temperature,CuIn1-xMnxTe2 shows paramagnetism.With increasing of M content,the magnetization and magnetic susceptibility increased.CuIn1-xCoxTe2 and CuIn1-xCoxSe2 compounds show ferromagnetismant at room temperature,both of the magnetization and saturation magnetization are increased with the increaseing of Co content.x-T curve shows three magnetic transitions in low temperature and M-T curve shows the Curie temperature of CuIn0.9Co0.1Te2 is about 980K.From the differential thermal,we can conclude that CuIn0.9Co0.1Te2 react endothermicly in the temperature of 0-1000K.By the standard four-probe method,the results tell us that CuInTe2 and CuIn0.9Co0.1Te2 show the properties of semiconductors.Through ultraviolet spectrophotometer,the results show the data of absorption band-gaps for CuIn-1-xMnxTe2,CuIn1-xCoxTe2,CuIn1-xCoxSe2,Cu1-xCoxInTe2 compounds are 1.06eV-1.60eV,1.06eV-1.61eV,1.25eV-1.53eV and 1.08eV-1.39eV respectively.Doping with magnetic elements can effectively adjust the absorption band-gaps to the optimal values of the solar energy requirements.