In this study, a first-principles study using the spin-polarized density functional theory approa... more In this study, a first-principles study using the spin-polarized density functional theory approach within corrected functional was carried out to investigate the electronic features of manganese oxide surfaces under three situations of (a) cation vacancy, (b) intercalation of multi- and univalent ions, and (c) adsorption of a water molecule upon the surface as catalytic performance. The possibility of obtaining the significant absolute magnetic momentum phases from native defects in orthorhombic structures of Mn2O3 and Mn3O4 (001) surface is explored, whereas Mn vacancy provides a transition from the insulating phase into a metal-like nature and modifies the electronic transport. Moreover, bandgap engineering via impurity intercalation has been explored. Ca+2 and Al+3 intercalations have manifested substantial attributes and explain the experimental results as efficient conducting system and catalytic activity. Furthermore, the adsorption of one water molecule and the most stable configuration, adsorption energies and electronic properties were thoroughly discussed. Accordingly, it was explored that H2O: Mn2O3 and Mn3O4 exhibit suitable parameters as efficient catalytic synthesis
Energy band-gap engineering via impurity intercalation into the 2-D MoO3 bilayer lattice has been... more Energy band-gap engineering via impurity intercalation into the 2-D MoO3 bilayer lattice has been studied using density functional theory calculations, and the effects of various kinds of dopants on the electronic structure have been explored. The dopants were incorporated via both oxygen and molybdenum substitution. The results show that although the MoO3 bilayer is an indirect band-gap semiconductor with zero magnetization, doped molybdenum trioxide experiences a bandgap reduction and a pure magnetization. Based on the calculated results, impurity doping leads to the creation of impurity levels inside the band-gap, and thereby both types of conductivity (n-type and p-type) can be identified. The calculated impurity formation-energies indicate that Nb and W atoms can be readily incorporated into the MoO3 bilayer.
We did a density functional theory spin-polarized calculation based on pseudopotential method on ... more We did a density functional theory spin-polarized calculation based on pseudopotential method on the effect of both vacancy and substitutional impurity in the tungsten tri-oxide lattice. We investigated oxygen and tungsten vacancies and for substitutional dopants we used palladium (Pd), platinum (Pt) and gold (Au) atoms with the formula AxW1−xO3 and x = 0.125, 0.25, 0.375, 0.5. We obtained electronic band structure, density of states and magnetization of defected and doped WO3. The results show that in the presence of tungsten vacancy, WO3 acts as a semiconductor with an indirect band gap while oxygen vacancy induces a metallic behavior for WO3. Besides, for Pt and Pd the location of trap states lead to photoexcited hole capturing, which can improve photocurrent but for Au dopant, the trap states occur in the middle of the band gap as active recombination centers. Furthermore, both kind of vacancies and Pt dopant can induce magnetization in all values of x, while Pd and Au are less efficient in inducing magnetization.
In this paper we investigate the structure of molybdenum trioxide using density functional theory... more In this paper we investigate the structure of molybdenum trioxide using density functional theory and DFT+U approximation in two cases. At first the effect of substitutional doping with lithium and in the next step adsorption of Methane on (010) two layers slab have been studied. The results show that although bulk MoO3 is a wide and indirect band gap semiconductor, lithium induces metallic behavior. Moreover, adsorption of CH4 causes a hole transfer into the MoO3 bilayer and the gap reduces.
In this article using density functional theory and GGA approximation for exchange correlation en... more In this article using density functional theory and GGA approximation for exchange correlation energy, we study the mechanism of environmental pollutant gases of methane, hydrogen disulfide and ammonia on molybdenite bilayer. Our results show that adsorption energy for ammonia is more than others and it adsorbs better on bilayer. Moreover, MoS2 bilayer is a semiconductor with an indirect band gap. Adsorption of all three gases reduces the band gap and creates new states in the vicinity of valance band so that the systems change to a P-semiconductor type.
This paper, we study the electronic structure of ZnS in two phases of zinc-blend and wurtzite, us... more This paper, we study the electronic structure of ZnS in two phases of zinc-blend and wurtzite, using density functional theory within GGA+U for the exchange-correlation potential. Furthermore, the effects of Ag atoms as both substitutional impurity and adsorbent are considered. The results suggest that ZnS is a direct band gap semiconductor with a 3.51 and 3.79 eV for ZB and WZ structures, respectively. Indeed, we have found that both substitutional and adsorbent Ag atoms strongly alter the electronic structure, and improve the optical response of the system in visible and infrared spectrum.
In this paper, the relaxed structure of WO3 bulk has been studied by density functional theory te... more In this paper, the relaxed structure of WO3 bulk has been studied by density functional theory technique. The band structures and electronic density of states for WO3 bulk has been obtained. This calculations show that WO3 bulk in monoclinic phase is a direct gap semiconductor. Thereafter doped WO3 with different percent of lithium atoms which were placed in tungsten site has been considered and the changes in electronic and structural properties in comparison with pure WO3 were calculated. The results were described a new product, with metallic properties, ionized bonds and free of any magnetization.
In this study, a first-principles study using the spin-polarized density functional theory approa... more In this study, a first-principles study using the spin-polarized density functional theory approach within corrected functional was carried out to investigate the electronic features of manganese oxide surfaces under three situations of (a) cation vacancy, (b) intercalation of multi- and univalent ions, and (c) adsorption of a water molecule upon the surface as catalytic performance. The possibility of obtaining the significant absolute magnetic momentum phases from native defects in orthorhombic structures of Mn2O3 and Mn3O4 (001) surface is explored, whereas Mn vacancy provides a transition from the insulating phase into a metal-like nature and modifies the electronic transport. Moreover, bandgap engineering via impurity intercalation has been explored. Ca+2 and Al+3 intercalations have manifested substantial attributes and explain the experimental results as efficient conducting system and catalytic activity. Furthermore, the adsorption of one water molecule and the most stable configuration, adsorption energies and electronic properties were thoroughly discussed. Accordingly, it was explored that H2O: Mn2O3 and Mn3O4 exhibit suitable parameters as efficient catalytic synthesis
Energy band-gap engineering via impurity intercalation into the 2-D MoO3 bilayer lattice has been... more Energy band-gap engineering via impurity intercalation into the 2-D MoO3 bilayer lattice has been studied using density functional theory calculations, and the effects of various kinds of dopants on the electronic structure have been explored. The dopants were incorporated via both oxygen and molybdenum substitution. The results show that although the MoO3 bilayer is an indirect band-gap semiconductor with zero magnetization, doped molybdenum trioxide experiences a bandgap reduction and a pure magnetization. Based on the calculated results, impurity doping leads to the creation of impurity levels inside the band-gap, and thereby both types of conductivity (n-type and p-type) can be identified. The calculated impurity formation-energies indicate that Nb and W atoms can be readily incorporated into the MoO3 bilayer.
We did a density functional theory spin-polarized calculation based on pseudopotential method on ... more We did a density functional theory spin-polarized calculation based on pseudopotential method on the effect of both vacancy and substitutional impurity in the tungsten tri-oxide lattice. We investigated oxygen and tungsten vacancies and for substitutional dopants we used palladium (Pd), platinum (Pt) and gold (Au) atoms with the formula AxW1−xO3 and x = 0.125, 0.25, 0.375, 0.5. We obtained electronic band structure, density of states and magnetization of defected and doped WO3. The results show that in the presence of tungsten vacancy, WO3 acts as a semiconductor with an indirect band gap while oxygen vacancy induces a metallic behavior for WO3. Besides, for Pt and Pd the location of trap states lead to photoexcited hole capturing, which can improve photocurrent but for Au dopant, the trap states occur in the middle of the band gap as active recombination centers. Furthermore, both kind of vacancies and Pt dopant can induce magnetization in all values of x, while Pd and Au are less efficient in inducing magnetization.
In this paper we investigate the structure of molybdenum trioxide using density functional theory... more In this paper we investigate the structure of molybdenum trioxide using density functional theory and DFT+U approximation in two cases. At first the effect of substitutional doping with lithium and in the next step adsorption of Methane on (010) two layers slab have been studied. The results show that although bulk MoO3 is a wide and indirect band gap semiconductor, lithium induces metallic behavior. Moreover, adsorption of CH4 causes a hole transfer into the MoO3 bilayer and the gap reduces.
In this article using density functional theory and GGA approximation for exchange correlation en... more In this article using density functional theory and GGA approximation for exchange correlation energy, we study the mechanism of environmental pollutant gases of methane, hydrogen disulfide and ammonia on molybdenite bilayer. Our results show that adsorption energy for ammonia is more than others and it adsorbs better on bilayer. Moreover, MoS2 bilayer is a semiconductor with an indirect band gap. Adsorption of all three gases reduces the band gap and creates new states in the vicinity of valance band so that the systems change to a P-semiconductor type.
This paper, we study the electronic structure of ZnS in two phases of zinc-blend and wurtzite, us... more This paper, we study the electronic structure of ZnS in two phases of zinc-blend and wurtzite, using density functional theory within GGA+U for the exchange-correlation potential. Furthermore, the effects of Ag atoms as both substitutional impurity and adsorbent are considered. The results suggest that ZnS is a direct band gap semiconductor with a 3.51 and 3.79 eV for ZB and WZ structures, respectively. Indeed, we have found that both substitutional and adsorbent Ag atoms strongly alter the electronic structure, and improve the optical response of the system in visible and infrared spectrum.
In this paper, the relaxed structure of WO3 bulk has been studied by density functional theory te... more In this paper, the relaxed structure of WO3 bulk has been studied by density functional theory technique. The band structures and electronic density of states for WO3 bulk has been obtained. This calculations show that WO3 bulk in monoclinic phase is a direct gap semiconductor. Thereafter doped WO3 with different percent of lithium atoms which were placed in tungsten site has been considered and the changes in electronic and structural properties in comparison with pure WO3 were calculated. The results were described a new product, with metallic properties, ionized bonds and free of any magnetization.
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Papers by Masoud Mansouri
reduction and a pure magnetization. Based on the calculated results, impurity doping leads to the creation of impurity levels inside the band-gap, and thereby both types of conductivity (n-type and p-type) can be identified. The calculated impurity formation-energies indicate that Nb and W
atoms can be readily incorporated into the MoO3 bilayer.
reduction and a pure magnetization. Based on the calculated results, impurity doping leads to the creation of impurity levels inside the band-gap, and thereby both types of conductivity (n-type and p-type) can be identified. The calculated impurity formation-energies indicate that Nb and W
atoms can be readily incorporated into the MoO3 bilayer.