In this study, based on the first-principles calculations, we systematically investigated the electronic and magnetic properties of the transition metal-oxide-incorporated 2D g-C3N4 nanosheet （labeled C3N4- TM-O, TM ...In this study, based on the first-principles calculations, we systematically investigated the electronic and magnetic properties of the transition metal-oxide-incorporated 2D g-C3N4 nanosheet （labeled C3N4- TM-O, TM - Sc-Mn）. The results suggest that the TM-O binds to g-CaN4 nanosheets strongly for all systems. We found that the 2D C3N4-TM-O framework is ferromagnetic for TM = Sc, Ti, V, Cr, while it is antiferromagnetic for TM = Mn. All the ferromagnetic systems exhibit the half-metallic property. Furthermore, Monte Carlo simulations based on the Heisenberg model suggest that the Curie temperatures （To） of the CaN4-TM-O （TM --- Sc, Ti, V, Cr） framework are 169 K, 68 K, 203 K, and 190 K, respectively. Based on Bader charge analysis, we found that the origin of the half-metallicity at Fermi energy can be partially attributed to the transfer of electrons from TM atoms to the g-C3N4 nanosheet. In addition, we found that not only electrons but also holes can induce half-metallicity for 2D g-C3N4 nanosheets, which may help to understand the origin of half-metallicity for graphitic carbon nitride.展开更多
The influence of temperature on the dielectric properties of sol-gel routed spin-coated molybdenum trioxide(MoO_(3)) thin film has been investigated.Prepared films were annealed at temperatures 250℃,350℃ and 400℃.T...The influence of temperature on the dielectric properties of sol-gel routed spin-coated molybdenum trioxide(MoO_(3)) thin film has been investigated.Prepared films were annealed at temperatures 250℃,350℃ and 400℃.The phase transformation from amorphous to-orthorhombic phase with preferential orientation(022)has been found by XRD for the film annealed above 250℃.The vibration modes of-orthorhombic MoO_(3) have been examined by Raman spectrum.The predominant Raman's band of-orthorhombic MoO_(3) thin film has been found at the frequency range 1000–600 cm^(-1).Using the UV–Vis spectrum,the band gap of the film is found to be 3.3–3.8 eV.The surface morphology of the MoO_(3) films has been examined by scanning electron microscope.The AC conductivity measurement of the MoO_(3) film has been carried out in the frequency range 10–10^(6) Hz.The frequency dependence of the impedance has been plotted in the complex plane.The variation of the capacitance and dielectric constant of MoO_(3) film with respect to temperature and frequency has been analyzed.Tunability of capacitance and figure of merit of the film are also determined.展开更多
文摘In this study, based on the first-principles calculations, we systematically investigated the electronic and magnetic properties of the transition metal-oxide-incorporated 2D g-C3N4 nanosheet （labeled C3N4- TM-O, TM - Sc-Mn）. The results suggest that the TM-O binds to g-CaN4 nanosheets strongly for all systems. We found that the 2D C3N4-TM-O framework is ferromagnetic for TM = Sc, Ti, V, Cr, while it is antiferromagnetic for TM = Mn. All the ferromagnetic systems exhibit the half-metallic property. Furthermore, Monte Carlo simulations based on the Heisenberg model suggest that the Curie temperatures （To） of the CaN4-TM-O （TM --- Sc, Ti, V, Cr） framework are 169 K, 68 K, 203 K, and 190 K, respectively. Based on Bader charge analysis, we found that the origin of the half-metallicity at Fermi energy can be partially attributed to the transfer of electrons from TM atoms to the g-C3N4 nanosheet. In addition, we found that not only electrons but also holes can induce half-metallicity for 2D g-C3N4 nanosheets, which may help to understand the origin of half-metallicity for graphitic carbon nitride.
文摘The influence of temperature on the dielectric properties of sol-gel routed spin-coated molybdenum trioxide(MoO_(3)) thin film has been investigated.Prepared films were annealed at temperatures 250℃,350℃ and 400℃.The phase transformation from amorphous to-orthorhombic phase with preferential orientation(022)has been found by XRD for the film annealed above 250℃.The vibration modes of-orthorhombic MoO_(3) have been examined by Raman spectrum.The predominant Raman's band of-orthorhombic MoO_(3) thin film has been found at the frequency range 1000–600 cm^(-1).Using the UV–Vis spectrum,the band gap of the film is found to be 3.3–3.8 eV.The surface morphology of the MoO_(3) films has been examined by scanning electron microscope.The AC conductivity measurement of the MoO_(3) film has been carried out in the frequency range 10–10^(6) Hz.The frequency dependence of the impedance has been plotted in the complex plane.The variation of the capacitance and dielectric constant of MoO_(3) film with respect to temperature and frequency has been analyzed.Tunability of capacitance and figure of merit of the film are also determined.
