Study On Electronic And Optical Properties Of Cs-Pb Doped Indium Iodide

Owing to its wider band gap, higher atomic number, larger resistivity and larger carrier mobility, that is, Indium Iodide has become one of the research focus in the field of nuclear radiation detectors in recent years. At present, the research on indium iodide concentrates on the purity of indium iodide and the influence the inherent defects have on nuclear detection performance, and crystal doping is an effective way to modulate the performance of the electronic structure and improve the material properties. Based on the background above. Based on the first principle of the Materials Studio software, the electronic structure and optical properties of CS doped indium iodide crystal, Pb doped indium iodide crystal and the CS、Pb doped indium iodide crystal were calculated and analysed in this paper.First of all, Pure indium iodide supercell model is established and the structure is optimized by using the CASTEP module of Materials Studio software. On the basis of the successful structural optimization, different Cs doping concentration models were established, the energy band structure, density of States, different charge density and optical properties of the doped system were calculated and the reasons for the increase of the band gap width were also analyzed.Secondly, based on the supercell model of pure indium iodide, supercell models for different concentrations of Pb were set up. After successful structural optimization, the minimum optical band gap, the density of States, the difference charge density and the relative free electron concentration of the doped system are calculated. The variation of the effective mass and conductivity of the doped electrons is analyzed, and the reason of the decrease of the absorption coefficient is explained as well.Finally, based on the supercell model of pure indium iodide, The band gap, density of States and absorption spectra of the doped system were calculated for the Cs atom and Pb atom doped with the same concentration. Find out the reason why the band gap of the Indium Iodide is wider than the In_0.75Cs_0.125Pb_0.125 I super cell band gap. Relative electron concentration of In_0.75Cs_0.125Pb_0.125 I super cell entering the conduction band was calculated,The relationship between the conductivity of In0.875Pb0.125 I system and the electrical conductivity of In_0.75Cs_0.125Pb_0.125 I system was analyzed, the minimum optical band gap of the In_0.75Cs_0.125Pb_0.125 I super cell are calculated and the reason for the decrease of absorption coefficient was explained.