The Experts below are selected from a list of 129 Experts worldwide ranked by ideXlab platform

Markus Schubert - One of the best experts on this subject based on the ideXlab platform.

  • Quantification of Optical Deflection by Laser-structured ZnO:Al
    IEEE Journal of Photovoltaics, 2013
    Co-Authors: Marcel Berner, Marc Sämann, Ahmed Garamoun, Markus Schubert
    Abstract:

    A novel camera-based measurement setup fully quantifies the transmitted radiation deflected by textured front electrodes for thin-film solar cells. The conventional measurement of angular intensity distribution only analyzes one polar plane. The new setup examines the optical scattering and/or diffraction over the complete hemisphere. The hemispheric intensity distribution of laser-structured ZnO:Al proves reduced Specular Transmission and, hence, improved light trapping.

  • Short papers: Quantification of optical deflection by laser-structured ZnO:Al
    2012
    Co-Authors: Marcel Berner, Marc Sämann, Ahmed Garamoun, Markus Schubert
    Abstract:

    Anovel camera-based measurement setup fully quantifies the transmitted radiation deflected by textured front electrodes for thin-film solar cells. The conventional measurement of angular intensity distribution only analyzes one polar plane. The new setup examines the optical scattering and/or diffraction over the complete hemisphere. The hemispheric intensity distribution of laser-structured ZnO:Al proves reduced Specular Transmission and, hence, improved light trapping.

  • Electronic and optical properties of hot-wire-deposited microcrystalline silicon
    Journal of Non-crystalline Solids, 1998
    Co-Authors: R. Brüggemann, Markus Schubert, A. Hierzenberger, P. Reinig, M. Rojahn, S. Schweizer, H.n. Wanka, I. Zrinscak
    Abstract:

    Abstract We conducted a study on undoped and doped hydrogenated microcrystalline silicon ( μ c-Si) samples deposited by hot-wire chemical vapor deposition for determination of the structural, electronic and optical properties. Light scattering, investigated by total and Specular Transmission and reflection, as well as angular resolved measurements, results mainly from the surface but with an intrinsic contribution from the interior. The optical properties resemble that of monocrystalline Si: the refractive index in the visible, the reflectance peaks in the near ultraviolet which may only appear after surface polishing, and the absorption coefficient which is larger than in monocrystalline silicon and varies with sample thicknesses. Depending on the doping level, the dark conductivity prefactor and activation energy exhibit either normal or anti-Meyer–Neldel rule behavior. The mobility-lifetime product from steady state photoconductivity strongly depends on the position of the Fermi energy with a minimum for low p-type doping, suggesting the importance of information on the Fermi energy if the mobility-lifetime product is given as an indicator for material quality of microcrystalline Si.

Erping Li - One of the best experts on this subject based on the ideXlab platform.

  • first principles calculation of effect of graphene coating on Transmission coefficient of cu thin film with low surface roughness
    Journal of Applied Physics, 2019
    Co-Authors: Manareldeen Ahmed, Erping Li
    Abstract:

    In this paper, we calculate the effect of a graphene coating on the Transmission coefficient of a Cu thin film with surface disorder. The nonequilibrium coherent potential approximation combined with the linear muffin-tin orbital formulation, which is based on first principles, is applied by assuming that there is surface disorder. The graphene coating mitigates the effect of Cu surface scattering on the Transmission coefficient. The weak interaction between Cu and graphene and the upward shift of the Fermi level with respect to the Dirac point improve the transport characteristics by offering more conduction bands. Moreover, graphene-coated Cu with a perfect surface has a completely Specular Transmission coefficient. The surface disorder decreases the Transmission coefficient due to the nonconserved transverse momentum ( k) of the scattering wave through the central area of the two-probe system. However, for a graphene coating on a Cu thin film with surface disorder x < 3.90 %, length l < 5.09 nm, width 0.25 nm, and thickness 1.23 nm, the Transmission coefficient is higher. The increased Transmission coefficient due to graphene coating can overcome the diffusive scattering originating from the surface disorder. The coherent potential approximation band structure shows that graphene bands are less affected by Cu surface disorder than Cu bands, which enhances the total conduction by offering additional channels for electrons. Our results demonstrate that graphene is a potential liner material for a Cu thin film with low surface disorder.In this paper, we calculate the effect of a graphene coating on the Transmission coefficient of a Cu thin film with surface disorder. The nonequilibrium coherent potential approximation combined with the linear muffin-tin orbital formulation, which is based on first principles, is applied by assuming that there is surface disorder. The graphene coating mitigates the effect of Cu surface scattering on the Transmission coefficient. The weak interaction between Cu and graphene and the upward shift of the Fermi level with respect to the Dirac point improve the transport characteristics by offering more conduction bands. Moreover, graphene-coated Cu with a perfect surface has a completely Specular Transmission coefficient. The surface disorder decreases the Transmission coefficient due to the nonconserved transverse momentum ( k) of the scattering wave through the central area of the two-probe system. However, for a graphene coating on a Cu thin film with surface disorder x < 3.90 %, length l < 5.09 nm,...

Manareldeen Ahmed - One of the best experts on this subject based on the ideXlab platform.

  • first principles calculation of effect of graphene coating on Transmission coefficient of cu thin film with low surface roughness
    Journal of Applied Physics, 2019
    Co-Authors: Manareldeen Ahmed, Erping Li
    Abstract:

    In this paper, we calculate the effect of a graphene coating on the Transmission coefficient of a Cu thin film with surface disorder. The nonequilibrium coherent potential approximation combined with the linear muffin-tin orbital formulation, which is based on first principles, is applied by assuming that there is surface disorder. The graphene coating mitigates the effect of Cu surface scattering on the Transmission coefficient. The weak interaction between Cu and graphene and the upward shift of the Fermi level with respect to the Dirac point improve the transport characteristics by offering more conduction bands. Moreover, graphene-coated Cu with a perfect surface has a completely Specular Transmission coefficient. The surface disorder decreases the Transmission coefficient due to the nonconserved transverse momentum ( k) of the scattering wave through the central area of the two-probe system. However, for a graphene coating on a Cu thin film with surface disorder x < 3.90 %, length l < 5.09 nm, width 0.25 nm, and thickness 1.23 nm, the Transmission coefficient is higher. The increased Transmission coefficient due to graphene coating can overcome the diffusive scattering originating from the surface disorder. The coherent potential approximation band structure shows that graphene bands are less affected by Cu surface disorder than Cu bands, which enhances the total conduction by offering additional channels for electrons. Our results demonstrate that graphene is a potential liner material for a Cu thin film with low surface disorder.In this paper, we calculate the effect of a graphene coating on the Transmission coefficient of a Cu thin film with surface disorder. The nonequilibrium coherent potential approximation combined with the linear muffin-tin orbital formulation, which is based on first principles, is applied by assuming that there is surface disorder. The graphene coating mitigates the effect of Cu surface scattering on the Transmission coefficient. The weak interaction between Cu and graphene and the upward shift of the Fermi level with respect to the Dirac point improve the transport characteristics by offering more conduction bands. Moreover, graphene-coated Cu with a perfect surface has a completely Specular Transmission coefficient. The surface disorder decreases the Transmission coefficient due to the nonconserved transverse momentum ( k) of the scattering wave through the central area of the two-probe system. However, for a graphene coating on a Cu thin film with surface disorder x < 3.90 %, length l < 5.09 nm,...

  • First principles calculation of effect of graphene coating on Transmission coefficient of Cu thin film with low surface roughness
    Journal of Applied Physics, 2019
    Co-Authors: Manareldeen Ahmed
    Abstract:

    In this paper, we calculate the effect of a graphene coating on the Transmission coefficient of a Cu thin film with surface disorder. The nonequilibrium coherent potential approximation combined with the linear muffin-tin orbital formulation, which is based on first principles, is applied by assuming that there is surface disorder. The graphene coating mitigates the effect of Cu surface scattering on the Transmission coefficient. The weak interaction between Cu and graphene and the upward shift of the Fermi level with respect to the Dirac point improve the transport characteristics by offering more conduction bands. Moreover, graphene-coated Cu with a perfect surface has a completely Specular Transmission coefficient. The surface disorder decreases the Transmission coefficient due to the nonconserved transverse momentum ( k) of the scattering wave through the central area of the two-probe system. However, for a graphene coating on a Cu thin film with surface disorder x < 3.90 %, length l < 5.09 nm, width 0.25 nm, and thickness 1.23 nm, the Transmission coefficient is higher. The increased Transmission coefficient due to graphene coating can overcome the diffusive scattering originating from the surface disorder. The coherent potential approximation band structure shows that graphene bands are less affected by Cu surface disorder than Cu bands, which enhances the total conduction by offering additional channels for electrons. Our results demonstrate that graphene is a potential liner material for a Cu thin film with low surface disorder.

Daniel Lincot - One of the best experts on this subject based on the ideXlab platform.

  • Nucleation effects on structural and optical properties of electrodeposited zinc oxide on tin oxide
    Journal of Applied Electrochemistry, 2000
    Co-Authors: B. Canava, Daniel Lincot
    Abstract:

    Zinc oxide was electrodeposited from oxygenated aqueous solutions of zinc chloride at 80 C on tin oxide covered glass substrates. A new activation treatment for the substrate is established. This consists in the initial formation, in the deposition solution, of a thin metallic zinc layer (5–50 nm) converted to ZnO by in situ reoxidation. Variable densities of nucleation centers (with values approaching 1010 cm–2) are formed by this treatment. This allows control of the formation of a zinc oxide layer ranging from open deposits of isolated crystallites to compact and homogeneous layers. Compact layers have high Specular Transmission below the band gap value (3.5 eV), whereas open films exhibit extensive light scattering. The shapes of the current–time curves during deposition are discussed in terms of nucleation and structural effects. A possible influence of the semiconducting properties of the films is pointed out.

Marcel Berner - One of the best experts on this subject based on the ideXlab platform.

  • Quantification of Optical Deflection by Laser-structured ZnO:Al
    IEEE Journal of Photovoltaics, 2013
    Co-Authors: Marcel Berner, Marc Sämann, Ahmed Garamoun, Markus Schubert
    Abstract:

    A novel camera-based measurement setup fully quantifies the transmitted radiation deflected by textured front electrodes for thin-film solar cells. The conventional measurement of angular intensity distribution only analyzes one polar plane. The new setup examines the optical scattering and/or diffraction over the complete hemisphere. The hemispheric intensity distribution of laser-structured ZnO:Al proves reduced Specular Transmission and, hence, improved light trapping.

  • Short papers: Quantification of optical deflection by laser-structured ZnO:Al
    2012
    Co-Authors: Marcel Berner, Marc Sämann, Ahmed Garamoun, Markus Schubert
    Abstract:

    Anovel camera-based measurement setup fully quantifies the transmitted radiation deflected by textured front electrodes for thin-film solar cells. The conventional measurement of angular intensity distribution only analyzes one polar plane. The new setup examines the optical scattering and/or diffraction over the complete hemisphere. The hemispheric intensity distribution of laser-structured ZnO:Al proves reduced Specular Transmission and, hence, improved light trapping.