Robert Kykyneshi

Structural and transport properties of CuSc1−xMgxO2+y delafossites

Transport and structural properties of Mg-doped and O-intercalated sintered powders and polycrystalline films of CuSc1−xMgxO2+y are reported. Substitution of Mg for Sc systematically increases the p-type conductivity in CuSc1−xMgxO2 sintered powders, producing a maximum conductivity of 0.015S∕cm at x≈0.06. A similar level of conductivity is observed in transparent polycrystalline CuSc1−xMgxO2 films at the same doping level. Mg doping causes no significant increase in optical absorption at this level. Intercalation of oxygen into the delafossite structure leads to a much larger increase in p-type conductivity. In powders, the maximum conductivity is 0.5S∕cm at y=0.23 and x=0.05. In oxygen-intercalated films, the maximum conductivity was 25S∕cm, with the transparent films gradually darkening as oxygen is incorporated. Oxygen intercalation increases the a-axis lattice parameter of the delafossite structure in both films and powders, with a much smaller effect on the c-axis parameter. Two distinct phases with...

Electronic and optical properties of potential solar absorber Cu3PSe4

We theoretically investigate the electronic and optical properties of semiconductor Cu3PSe4. We also report diffuse reflectance spectroscopy measurements for Cu3PSe4 and Cu3PS4, which indicate a band gap of 1.40 eV for the former. Ab initio density functional theory (DFT) calculations based on hybrid functionals agree well with this value and reveal that the band gap is direct. Calculations yield an optical absorption spectrum similar to GaAs in the visible region, with α > 5 × 104 cm−1 for λ < 630 nm. We conclude that the optical properties of Cu3PSe4 are within the desired range for a photovoltaic solar absorber material.

Transparent Conducting Oxides Based on Tin Oxide

Tin oxide (SnO2) is an important and widely used wide band-gap semiconductor and is part of a family of binary transparent conducting oxides (TCO), such as Sn- and ZnO-doped In2O3 (ITO, ZIO) [1] and ZnO:Al [2], CdO. It is of great interest in corrosive environment applications due to its high stability. This includes applications such as batteries, low emission windows coatings, solar cells, etc. In this chapter we will introduce the structural, electrical and optical properties of undoped and doped tin oxides. In addition, thin films via various deposition methods are discussed.