Frist-principles Calculation Of CdS Optical Properties Doped With Cu、y And Ce

The semiconductors have good electrical and optical characters, which adjusted by doping in semiconductors. It is a significant application in solar cells, light-emitting materials, electronic devices, etc. Based on the above reasons, the study of intrinsic semiconductor and the doped semiconductors have received more and more attention.In recent years, many scholars have reporte the doped semiconductor of the infrared light, the light emitting materials biomarkers. Based on the density functional theory,we studied Cu, Y, and Ce doped CdS materials band structures caused by changes in the density of states, the electricals and optical properties and so on, and used the CASTEP in Materials Studio software. Our aim is exploring the causation elements and over by doping metal element changes and regulatory mechanisms, optical character and band gap of semiconductor material mining, we have completed the many studies, as follow.Firstly, we used first-principles to calculate the Cu-doped CdS for optimized geometry structures, and then calculated the energy band gap, absorption coefficient,the dielectric function and optical conductivity. The results showed the band gap was dcreased with the increasing doping copper concentration. Through the analysis, we found that doping of Cu element changes the energy band structure. The results show that the photoconduction of the 3Cu@CdS with higher doped concentration enhanced.Which is expected a photoelectric switch material. From the results of the analysis can also be obtained, 5Cu@CdS doped materials can emit light in the blue region, and the charactercan be used as biomarkers,Cu doped CdS materials absorbed a lot in the infrared region, and photoconduction strengthened distinctly,thus Cu can be becomed a dopant of enhance absorption of CdS infrared light. Cu doped CdS provides some conductive holes, these holes above the Fermi level, so that the doped materials in the infrared portion of the light-emitting and infrared light absorption has been strengthened by the calculating of electronic structure.Secondly, we have calaulated structed of doped Yttrium into cadmium sulfide,which was used the method of GGA + U, we first optimized geometry of the various dopant materials as same as copper doping. We then calculated the electronic structureand optical properties. The band gap of Y doped is slightly smaller than the intrinsic CdS band gap, because of the doping of Y elements provide lower conduction band energy, reducing the conduction band lower position. The calculative results show photonduction observal enhanced when doping concentration is 3Y@CdS, based on the character, it is used to the photoelectric conversion materials. Based on the Stokes shift, 3Y@CdS material will be as a blue light emitting material and it have an optical absorption peak also appears in the low-energy region. Therefore, those characters have a significant application in the biomarkers luminescent material.Experimentally,it had been low concentration quantum dots of Ce depoding by using thermal stuation and water blown. We calculated by the first-principles and the results as same as experimentally, and introducted the optics character of doping material in the states density and the band gap. Through the calculation, a low concentration doped material optical absorption has obvious enhancement in in the low energy region. Moreover, the photoconduction has obvious enhancement too.