Structural and optoelectronic properties of pure and Co doped In2O3 are studied by employing the full-potential linearized augmented plane wave method,which is known to produce highly accurate results.First principles...Structural and optoelectronic properties of pure and Co doped In2O3 are studied by employing the full-potential linearized augmented plane wave method,which is known to produce highly accurate results.First principles calculations are performed with ordinary generalized gradient approximation(GGA)along with new Hubbard and modified Becke-Johnson exchange(mBJ)potential techniques.Improved band gap results are obtained for In2O3 with GGA+U and mBJ.In the case of mBJ,the band gap values are 3.5 eV and 3.4 eV for rhombohedral and cubic phases,which are in close agreement with the experimental data.Substitution of In by Co 25%alters the energy gap and a spin splitting effect is observed in these phases.For the spin-up state,it remains semiconductor,whereas for the spin-down state it shows semimetallic behavior.The value of static refractive index n(0)is 1.74 for the cubic phase,while in rhombohedral phase the values of n(0)are 1.77 and 1.74 along xx and zz optical axes,respectively.The calculated optical properties conform anisotropy in the rhombohedral phase and these materials can be potential candidates for the optoelectronics applications.展开更多
The highly accurate full-potential linearized augmented plane wave plus local orbital method is employed to calculate the structural,electronic and transport properties of HgIn_(2)S_(4) and ZnIn_(2)S_(4).For ZnIn_(2)S...The highly accurate full-potential linearized augmented plane wave plus local orbital method is employed to calculate the structural,electronic and transport properties of HgIn_(2)S_(4) and ZnIn_(2)S_(4).For ZnIn_(2)S_(4),the calculated In–S bond length is in good agreement with the experimental data.Bulk moduli results suggest that ZnIn_(2)S_(4) can afford more compressional effects than HgIn_(2)S_(4).The present study confirms that both HgIn_(2)S_(4) and ZnIn_(2)S_(4) are indirect band gap materials with band gap values of 0.705 eV and 1.533 eV respectively.The localized region existing in the most bottom valance band of both materials splits into states by 1 eV energy difference under the spin orbital coupling effect.Contour plots of charge density predict that chemical bonding in these compounds is a mixture of ionic and covalent characteristics.Effective mass results reveal that mobility of charge carriers in ZnIn_(2)S_(4) is greater than that in HgIn_(2)S_(4).展开更多
We present the characteristics of the thermoluminescence (TL) response of Ge-doped optical fibers with various energies and exposures of photon irradiation.To investigate the Ge-doped SiO2 as an efficient TL material,...We present the characteristics of the thermoluminescence (TL) response of Ge-doped optical fibers with various energies and exposures of photon irradiation.To investigate the Ge-doped SiO2 as an efficient TL material,the TL responses are compared with commercially available standard TLD100 media.The Ge-doped optical fiber and TLD100 are placed in gelatin capsules and irradiated with x-ray using a Toshiba model KXO-15R x-ray generator.The Ge-doped fiber and TLD-100 show linear response as a function of current and time using x-ray photon of energy 60,80 and l00kV.When irradiated with 60,80 and l00kV x-ray energy at various currents (mA ),tube distance (cm) and exposure time (second) ranges,TLD100 media provide a TL yield up to two times that of Ge-doped fibers.The energy response of the Ge-doped fibers is linear and similar over the 60-l00 kVenergy range,and its sensitivity is 0.39±0.05 of the TLD100 media.The glow curves of TLD 100 and doped optical fiber are also compared.展开更多
The electronic band structure and optical parameters of SnMg_(2)O_(4) are investigated by the first-principles technique based on a new potential approximation known as modified Becke–Johnson(mBJ).The direct band gap...The electronic band structure and optical parameters of SnMg_(2)O_(4) are investigated by the first-principles technique based on a new potential approximation known as modified Becke–Johnson(mBJ).The direct band gap values by LDA,GGA and EV-GGA are underestimated significantly as compared to mBJ-GGA,which generally provides the results comparable to the experimental values.Similarly,the present band gap value(4.85 eV)using mBJ-GGA is greatly enhanced to the previous value by EV-GGA(2.823 eV).The optical parametric quantities(dielectric constant,index of refraction,reflectivity,optical conductivity and absorption coefficient)relying on the band structure are presented and examined.The first critical point(optical absorption's edge)in SnMg_(2)O_(4) occurs at about 4.85 eV.A strong absorption region is observed,extending between 5.4 eV to 25.0 eV.For SnMg_(2)O_(4),static dielectric constantε1(0),static refractive index n(0),and the magnitude of the coefficient of reflectivity at zero frequency R(0)are 2.296,1.515 and 0.0419,respectively.The optoelectronic properties indicate that this material can be successfully used in optical devices.展开更多
This work studies the systematic reduced transition probabilities B（E2）↓, intrinsic quadrupole moments and deformation parameters of Pd isotopes with even neutrons from N =62 to 66. The downward reduced transition ...This work studies the systematic reduced transition probabilities B（E2）↓, intrinsic quadrupole moments and deformation parameters of Pd isotopes with even neutrons from N =62 to 66. The downward reduced transition probabilities B（E2）↓from gamma transition 8^＋to 6^＋, 6^＋ to 4^＋, 4^＋ to 2^＋ and 2^＋ to 0＋states of even-even108 112Pd isotopes were calculated by the Interacting Boson Model（IBM-1） and compared with the available previous experimental results. The ratio of the excitation energies of the first 4＋and the first 2＋excited states, R4/2, is also studied for the classification of symmetry of these nuclei. Furthermore we have studied systematically the transition rate R = B（E2： L＋ →（L 2）＋）/B（E2 ： 2＋ →0＋） of some of the low-lying quadrupole collective states in comparison with the available experimental data. The associated quadrupole moments and deformation parameters have been calculated. The results of this calculation are in good agreement with the corresponding available experimental data. The108 112Pd isotopes show the O（6） symmetry.展开更多
文摘Structural and optoelectronic properties of pure and Co doped In2O3 are studied by employing the full-potential linearized augmented plane wave method,which is known to produce highly accurate results.First principles calculations are performed with ordinary generalized gradient approximation(GGA)along with new Hubbard and modified Becke-Johnson exchange(mBJ)potential techniques.Improved band gap results are obtained for In2O3 with GGA+U and mBJ.In the case of mBJ,the band gap values are 3.5 eV and 3.4 eV for rhombohedral and cubic phases,which are in close agreement with the experimental data.Substitution of In by Co 25%alters the energy gap and a spin splitting effect is observed in these phases.For the spin-up state,it remains semiconductor,whereas for the spin-down state it shows semimetallic behavior.The value of static refractive index n(0)is 1.74 for the cubic phase,while in rhombohedral phase the values of n(0)are 1.77 and 1.74 along xx and zz optical axes,respectively.The calculated optical properties conform anisotropy in the rhombohedral phase and these materials can be potential candidates for the optoelectronics applications.
基金Supported by Fund of the Ministry of Higher Education(MOHE)Malaysia under Grant No Q.J130000.2526.02H93Universiti Teknologi Malaysia(UTM)under Grant No JI30000.2526.03H78.
文摘The highly accurate full-potential linearized augmented plane wave plus local orbital method is employed to calculate the structural,electronic and transport properties of HgIn_(2)S_(4) and ZnIn_(2)S_(4).For ZnIn_(2)S_(4),the calculated In–S bond length is in good agreement with the experimental data.Bulk moduli results suggest that ZnIn_(2)S_(4) can afford more compressional effects than HgIn_(2)S_(4).The present study confirms that both HgIn_(2)S_(4) and ZnIn_(2)S_(4) are indirect band gap materials with band gap values of 0.705 eV and 1.533 eV respectively.The localized region existing in the most bottom valance band of both materials splits into states by 1 eV energy difference under the spin orbital coupling effect.Contour plots of charge density predict that chemical bonding in these compounds is a mixture of ionic and covalent characteristics.Effective mass results reveal that mobility of charge carriers in ZnIn_(2)S_(4) is greater than that in HgIn_(2)S_(4).
基金Supported by the Ministry of Higher Education(MOHE)of Malaysia under Grant No Q.J130000.7126.00J66Universiti Teknologi Malaysia(UTM).
文摘We present the characteristics of the thermoluminescence (TL) response of Ge-doped optical fibers with various energies and exposures of photon irradiation.To investigate the Ge-doped SiO2 as an efficient TL material,the TL responses are compared with commercially available standard TLD100 media.The Ge-doped optical fiber and TLD100 are placed in gelatin capsules and irradiated with x-ray using a Toshiba model KXO-15R x-ray generator.The Ge-doped fiber and TLD-100 show linear response as a function of current and time using x-ray photon of energy 60,80 and l00kV.When irradiated with 60,80 and l00kV x-ray energy at various currents (mA ),tube distance (cm) and exposure time (second) ranges,TLD100 media provide a TL yield up to two times that of Ge-doped fibers.The energy response of the Ge-doped fibers is linear and similar over the 60-l00 kVenergy range,and its sensitivity is 0.39±0.05 of the TLD100 media.The glow curves of TLD 100 and doped optical fiber are also compared.
基金Supported by the Fund for Foreign Academic Visitors of Universiti Teknologi Malaysia(UTM)Skudai,Johor,Malaysia under Grant No JI3000077264D035.
文摘The electronic band structure and optical parameters of SnMg_(2)O_(4) are investigated by the first-principles technique based on a new potential approximation known as modified Becke–Johnson(mBJ).The direct band gap values by LDA,GGA and EV-GGA are underestimated significantly as compared to mBJ-GGA,which generally provides the results comparable to the experimental values.Similarly,the present band gap value(4.85 eV)using mBJ-GGA is greatly enhanced to the previous value by EV-GGA(2.823 eV).The optical parametric quantities(dielectric constant,index of refraction,reflectivity,optical conductivity and absorption coefficient)relying on the band structure are presented and examined.The first critical point(optical absorption's edge)in SnMg_(2)O_(4) occurs at about 4.85 eV.A strong absorption region is observed,extending between 5.4 eV to 25.0 eV.For SnMg_(2)O_(4),static dielectric constantε1(0),static refractive index n(0),and the magnitude of the coefficient of reflectivity at zero frequency R(0)are 2.296,1.515 and 0.0419,respectively.The optoelectronic properties indicate that this material can be successfully used in optical devices.
基金King Abdulaziz University for supportin this workthe Ministry of Higher Education (MOHE) Malaysia/Universiti Teknologi Malaysia (UTM) for supporting this research work
文摘This work studies the systematic reduced transition probabilities B（E2）↓, intrinsic quadrupole moments and deformation parameters of Pd isotopes with even neutrons from N =62 to 66. The downward reduced transition probabilities B（E2）↓from gamma transition 8^＋to 6^＋, 6^＋ to 4^＋, 4^＋ to 2^＋ and 2^＋ to 0＋states of even-even108 112Pd isotopes were calculated by the Interacting Boson Model（IBM-1） and compared with the available previous experimental results. The ratio of the excitation energies of the first 4＋and the first 2＋excited states, R4/2, is also studied for the classification of symmetry of these nuclei. Furthermore we have studied systematically the transition rate R = B（E2： L＋ →（L 2）＋）/B（E2 ： 2＋ →0＋） of some of the low-lying quadrupole collective states in comparison with the available experimental data. The associated quadrupole moments and deformation parameters have been calculated. The results of this calculation are in good agreement with the corresponding available experimental data. The108 112Pd isotopes show the O（6） symmetry.
