In order to investigate the effect of Ag doping(ZnS(Ag)) and Zn vacancy(V_(Zn)) on the alpha particle detection performance of wurtzite(WZ) ZnS as a scintillation cell component, the electronic structure and optical p...In order to investigate the effect of Ag doping(ZnS(Ag)) and Zn vacancy(V_(Zn)) on the alpha particle detection performance of wurtzite(WZ) ZnS as a scintillation cell component, the electronic structure and optical properties of ZnS, ZnS(Ag), and V_(Zn)were studied by firstprinciple calculation based on the density functional theory. The results show that the band gaps of ZnS, ZnS(Ag),and V_(Zn)are 2.17, 1.79, and 2.37 eV, respectively. Both ZnS(Ag) and V_(Zn)enhance the absorption and reflection of the low energy photons. A specific energy, about 2.9 eV,leading to decrease of detection efficiency is observed. The results indicate that Ag doping has a complex effect on the detection performance. It is beneficial to produce more visible light photons than pure WZ ZnS when exposed to the same amount of radiation, while the increase of the absorption to visible light photons weakens the detection performance. Zn vacancy has negative effect on the detection performance. If we want to improve the detection performance of WZ ZnS, Ag doping will be a good way,but we should reduce the absorption to visible light photons and control the number of Zn vacancy rigorously.展开更多
The electronic structure and optical properties of CdGeAs2 were calculated by the first principle method using ultra-soft pseudo-potential approach of the plane wave based upon density functional theory （DFT）. Mulli...The electronic structure and optical properties of CdGeAs2 were calculated by the first principle method using ultra-soft pseudo-potential approach of the plane wave based upon density functional theory （DFT）. Mulliken population analysis showed that atomic orbital hybridization occurs when forming chemical bonds. The relationship between inter-band transition and optical properties was analyzed to provide a theoretical basis for investigating or controlling CdGeAs2 crystal defects.展开更多
A first-principles study has been performed to calculate the electronic and optical properties of the SbxSn1xO system.The simulations are based upon the method of generalized gradient approximations with the Perdew-Bu...A first-principles study has been performed to calculate the electronic and optical properties of the SbxSn1xO system.The simulations are based upon the method of generalized gradient approximations with the Perdew-Burke-Ernzerhof form in the framework of density functional theory.The supercell structure shows a trend from expanding to shrinking with the increasing Sb concentration.The increasing Sb concentration induces the band gap narrowing.Optical transition has shifted to the low energy range with increasing Sb concentration.Other important optical constants such as the dielectric function,reflectivity,refractive index,and electron energy loss function for Sb-doped SnO2 are discussed.The optical absorption edge of SnO2 doped with Sb also shows a redshift.展开更多
The electronic structures and optical properties of intrinsic β-Ga2O3 and Zn-dopedβ-Ga2O3 are investigated by first-principles calculations. The analysis about the thermal stability shows that Zn-doped β-Ga2O3 rema...The electronic structures and optical properties of intrinsic β-Ga2O3 and Zn-dopedβ-Ga2O3 are investigated by first-principles calculations. The analysis about the thermal stability shows that Zn-doped β-Ga2O3 remains stable. The Zn doping does not change the basic electronic structure of β-Ga2O3, but only generates an empty energy level above the maximum of the valence band, which is shallow enough to make the Zn-doped β-Ga2O3 a typical p-type semiconductor. Because of Zn doping, absorption and reflectivity are enhanced in the near infrared region. The higher absorption and reflectivity of ZnGa（2） than those of ZnGa（1） are due to more empty energy states of ZnGa（2） than those of ZnGa（1） near Ef in the near infrared region.展开更多
Columbite Zn0.8Co0.2Nb2O6 crystals were grown by optical floating zone methods. The x-ray diffraction(XRD) was used to check the structure information of the grown Zn0.8Co0.2Nb2O6 crystal. The room temperature and tem...Columbite Zn0.8Co0.2Nb2O6 crystals were grown by optical floating zone methods. The x-ray diffraction(XRD) was used to check the structure information of the grown Zn0.8Co0.2Nb2O6 crystal. The room temperature and temperature-dependent Raman spectra were tested to investigate the optical phonon behaviors of columbite Zn0.8Co0.2Nb2O6, which exhibited a temperature stable property. The magnetics properties of Zn0.8Co0.2Nb2O6, measured by a physical property measurement system(PPMS), were also presented in this work.展开更多
基金supported by the National Natural Science Foundation of China(Nos.11275071 and 11305061)the Fundamental Research Funds for the Central Universities(Nos.2014MS53 and 2014ZZD09)the Student’s Platform for Innovation and Entrepreneurship Training Program of North China Electric Power University(No.15129)
文摘In order to investigate the effect of Ag doping(ZnS(Ag)) and Zn vacancy(V_(Zn)) on the alpha particle detection performance of wurtzite(WZ) ZnS as a scintillation cell component, the electronic structure and optical properties of ZnS, ZnS(Ag), and V_(Zn)were studied by firstprinciple calculation based on the density functional theory. The results show that the band gaps of ZnS, ZnS(Ag),and V_(Zn)are 2.17, 1.79, and 2.37 eV, respectively. Both ZnS(Ag) and V_(Zn)enhance the absorption and reflection of the low energy photons. A specific energy, about 2.9 eV,leading to decrease of detection efficiency is observed. The results indicate that Ag doping has a complex effect on the detection performance. It is beneficial to produce more visible light photons than pure WZ ZnS when exposed to the same amount of radiation, while the increase of the absorption to visible light photons weakens the detection performance. Zn vacancy has negative effect on the detection performance. If we want to improve the detection performance of WZ ZnS, Ag doping will be a good way,but we should reduce the absorption to visible light photons and control the number of Zn vacancy rigorously.
基金supported by the National Natural Science Foundation of China (E5057201)Heilongjiang Provincial Scientific and Technological Projects
文摘The electronic structure and optical properties of CdGeAs2 were calculated by the first principle method using ultra-soft pseudo-potential approach of the plane wave based upon density functional theory （DFT）. Mulliken population analysis showed that atomic orbital hybridization occurs when forming chemical bonds. The relationship between inter-band transition and optical properties was analyzed to provide a theoretical basis for investigating or controlling CdGeAs2 crystal defects.
基金Supported by the Fundamental Research Funds for the Central Universities under Grant No. BUPT2009RC0412the National Natural Science Foundation of China under Grant Nos. 60908028 and 60971068
文摘A first-principles study has been performed to calculate the electronic and optical properties of the SbxSn1xO system.The simulations are based upon the method of generalized gradient approximations with the Perdew-Burke-Ernzerhof form in the framework of density functional theory.The supercell structure shows a trend from expanding to shrinking with the increasing Sb concentration.The increasing Sb concentration induces the band gap narrowing.Optical transition has shifted to the low energy range with increasing Sb concentration.Other important optical constants such as the dielectric function,reflectivity,refractive index,and electron energy loss function for Sb-doped SnO2 are discussed.The optical absorption edge of SnO2 doped with Sb also shows a redshift.
基金Project supported by the National Natural Science Foundation of China(Grant No.10974077)the Natural Science Foundation of Shandong Province,China(Grant No.2009ZRB01702)the Shandong Provincial Higher Educational Science and Technology Program,China(Grant No.J10LA08)
文摘The electronic structures and optical properties of intrinsic β-Ga2O3 and Zn-dopedβ-Ga2O3 are investigated by first-principles calculations. The analysis about the thermal stability shows that Zn-doped β-Ga2O3 remains stable. The Zn doping does not change the basic electronic structure of β-Ga2O3, but only generates an empty energy level above the maximum of the valence band, which is shallow enough to make the Zn-doped β-Ga2O3 a typical p-type semiconductor. Because of Zn doping, absorption and reflectivity are enhanced in the near infrared region. The higher absorption and reflectivity of ZnGa（2） than those of ZnGa（1） are due to more empty energy states of ZnGa（2） than those of ZnGa（1） near Ef in the near infrared region.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0403704)the National Natural Science Foundation of China(Grant Nos.11304113,11474127,and 11574112)the Fundamental Research Funds for the Central Universities of China
文摘Columbite Zn0.8Co0.2Nb2O6 crystals were grown by optical floating zone methods. The x-ray diffraction(XRD) was used to check the structure information of the grown Zn0.8Co0.2Nb2O6 crystal. The room temperature and temperature-dependent Raman spectra were tested to investigate the optical phonon behaviors of columbite Zn0.8Co0.2Nb2O6, which exhibited a temperature stable property. The magnetics properties of Zn0.8Co0.2Nb2O6, measured by a physical property measurement system(PPMS), were also presented in this work.
