The factors limiting the conductivity of fluorine-doped tin dioxide (FTO) produced via atmospheric pressure chemical vapor deposition are investigated. Modeling of the transport properties indicates that the measured Hall effect mobilities are far below the theoretical ionized impurity scattering limit. Significant compensation of donors by acceptors is present with a compensation ratio of 0.5, indicating that for every two donors there is approximately one acceptor. Hybrid density functional theory calculations of defect and impurity formation energies indicate the most probable acceptor-type defects. The fluorine interstitial defect has the lowest formation energy in the degenerate regime of FTO. Fluorine interstitials act as singly charged acceptors at the high Fermi levels corresponding to degenerately n-type films. X-ray photoemission spectroscopy of the fluorine impurities is consistent with the presence of substitutional F O donors and interstitial F i in a roughly 2:1 ratio in agreement with the compensation ratio indicated by the transport modeling. Quantitative analysis through Hall effect, X-ray photoemission spectroscopy, and calibrated secondary ion mass spectrometry further supports the presence of compensating fluorine-related defects.

Antimony selenide (Sb 2 Se 3) is an emerging chalcogenide photovoltaic absorber material that has been the subject of increasing interest in recent years, demonstrating rapid efficiency increases with a material that is simple, abundant, and stable. This paper examines the material from both a theoretical and practical standpoint. The theoretical viability of Sb 2 Se 3 as a solar photovoltaic material is assessed and the maximum spectroscopically limited performance is estimated, with a 200 nm film expected to be capable of achieving a photon conversion efficiency of up to 28.2%. By adapting an existing CdTe close-spaced sublimation (CSS) process, Sb 2 Se 3 material with large rhubarb-like grains is produced and solar cells are fabricated. We show that the established CdS window layer is unsuitable for use with CSS, due to intermixing during higher temperature processing. Substituting CdS with the more stable TiO 2 , a power conversion efficiency of 5.5% and an open-circuit voltage V o c of 0.45 V are achieved; the voltage exceeding current champion devices. This paper demonstrates the potential of CSS for scalable Sb 2 Se 3 deposition and highlights the Manuscript

Superior transparent conducting properties of indium oxide realised by molybdenum donors resonant in the conduction band, avoiding detrimental effects of tin doping.

The candidate photovoltaic absorber antimony selenide Sb2Se3 has been prepared by the commercially attractive close-space sublimation method. Structure, composition, and morphology are studied by x-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. Large rhubarb-like grains favorable for photovoltaics naturally develop. The temperature-dependence of the direct band gap is determined by photoreflectance between 20 and 320 K and is well described by the Varshni and Bose–Einstein relations, blue-shifting with decreasing temperature from 1.18 to 1.32 eV. The 300 K band gap matches that seen in high quality single-crystal material, while the 0 K gap is consistent with that found in first-principles calculations, further supporting the array of beneficial photovoltaic properties indicated for this material.