Bulk properties of CuSc₁₋ₓMgₓO₂, CuSc₁₋ₓMgₓO₂₊y, BaCu₂S₂, Bai₁₋ₓKCu₂S₂, BaCu₂Se₂
and Bai₁₋ₓKₓCu₂Se₂ are investigated supporting the search for highly conductive p-type
thin films. Mg is an efficient dopant in CuScO₂ with conductivity up to l.5.10⁻² S/cm.
Oxidation of CuScO₂:Mg leads to further increase in conductivity up to 0.5 S/cm. The
amount of...
Double excitonic absorption peaks are observed in textured BaCuSF and BaCuSeF thin films. The excitonic doublet separation increases with increasing fraction of heavy chalcogen in the thin-film solid solutions, in good agreement with the spin-orbit splitting of the valence bands calculated by density-functional theory. In BaCuSF and BaCuSeF, the excitons...
Transport and structural properties of Mg-doped and O-intercalated sintered powders and
polycrystalline films of CuSc₁₋ₓMgₓO[subscript 2+y] are reported. Substitution of Mg for Sc systematically
increases the p-type conductivity in CuSc₁₋ₓMgₓO₂ sintered powders, producing a maximum
conductivity of 0.015 S/cm at x≈0.06. A similar level of conductivity is observed in transparent...
In situ photoemission spectroscopy experiments are used to characterize the interface between ZnTe and the wide band gap p-type semiconductor BaCuSeF. The contact is characterized by a null valence-band offset, a large conduction-band offset, and a chemically graded interface. By applying the transitivity rule for band offset and on the...
Zinc tin oxide (ZTO) films deposited by pulsed laser deposition (PLD) are
investigated as a channel layers for transparent thin-film transistors (TTFTs).
Films are deposited on glass for characterization, and transistor channel layers are
deposited onto aluminum oxide-titanium oxide/tin doped indium oxide/glass
substrates (ATO/ITO/glass) to produce TTFTs.
UV-visible spectroscopy on...
BaCuChF (Ch = S, Se, Te) materials are chalcogen-based transparent conductors with wide optical band gaps (2.9 – 3.5 eV) and a high concentration of free holes (10¹⁸ – 10²⁰ cm⁻³) caused by the presence of copper vacancies. Chalcogen vacancies compensate copper vacancies in these materials, setting the Fermi level...
Native point defects, defect complexes, and oxygen impurities in BaCuChF were studied using density
functional theory calculations, self-consistent thermodynamic simulations, and various experimental techniques.
Unintentional p-type conductivity in BaCuChF is explained by the presence of copper vacancies with
transition levels in the valence band. These acceptor-like defects are partially compensated...
BaCuChF (Ch=S,Se,Te) surfaces and BaCuSeF interfaces with zinc phthalocyanine (ZnPc) were studied by photoelectron spectroscopy. BaCuChF compounds oxidize when exposed to ambient atmosphere. Se capping layers were studied as a means to produce representative surfaces for photoelectron spectroscopic measurements. Decapped BaCuSeF surfaces remain O-free and C-free when the Se layer...
SnS is a potential earth-abundant photovoltaic (PV) material. Employing both theory and experiment to assess the PV relevant properties of SnS, we clarify on whether SnS has an indirect or direct band gap and what is the minority carrier effective mass as a function of the film orientation. SnS has...
The electronic structure of the oxychalcogenides LaCuOSe and BiCuOSe has been studied using O K-edge x-ray emission spectroscopy, x-ray absorption spectroscopy, and density functional theory, in order to examine the effects of the M³⁺ ion configurations. The known distortion of the BiO layers in BiCuOSe compared to the LaO layers...