Zinc nitride films were deposited on glass or silicon substrates by reactive magnetron RF sputtering of zinc in N2–Ar ambient. The deposition conditions were optimized in terms of substrate temperature and N2/Ar sputtering gas ratio, and representative films were then studied by structure, optical and spectroscopy techniques, and electrical measurements. Spectroscopic ellipsometry and spectrophotometry measurements revealed that the material has a direct band gap close to 1.26 eV. Hall effect and resistivity measurements indicated n-type conductivity with a very high carrier concentration of about1021 cm−3, mobility of up to 90 cm2 V−1 s−1, and resistivity of ∼10−3 Ω cm. X-ray photoelectron spectroscopy spectra clearly showed the existence of not only Zn–N bonding but also of a fraction of N–N bonding configurations, together with an oxidized surface. According to energy-dispersive x-ray spectroscopy analysis, the as-deposited films were almost stoichiometric and contained only a small fraction of oxygen.

No abstract

No abstract

Zinc nitride and oxy-nitride thin films were prepared by reactive magnetron rf sputtering of zinc in either nitrogen-argon or nitrogen-argon-oxygen ambient. The effects of varying the total sputtering pressure and the oxygen fraction in the total sputtering gas mixture on the microstructure, electrical and optical properties were investigated. With increasing the sputtering pressure, the dominant phase comprising the film material changes from the crystalline zinc nitride phase to crystalline zinc oxide. The characteristic pressure, at which this change in the dominant phase is observed, decreases with the increase of the oxygen fraction in the total sputtering gas mixture. The increase of the oxygen content in the films (from 5 at.% to a maximum of 40 at.%) and the downward shift in the optical absorption edge (from 920 to 400 nm), combined with the x-ray diffraction data, support these observations, indicating the controllable fabrication of an oxy-nitride film material. Correlations between the films' fabrication conditions, including post-deposition annealing, their structure and composition, and their electrical properties are examined as well.

We examine the potential of Bi-Ge-Se chalcogenide glass films as materials for a new type of photovoltaic devices, referred to as junctionless nanodipole PV. Glasses of a chemical composition providing a significant optical absorption were synthesized in quartz ampoules from high-purity Bi, Ge, and Se elements by a conventional melt quenching technique. This material was then used to deposit thin films with different thicknesses on various substrates by thermal evaporation under high-vacuum conditions. The original bulk glasses and the films were characterized by electron microscopy with EDS, XRD, Raman spectroscopy, differential scanning calorimetry, and spectrophotometry. Open-circuit voltage (V oc ) readings under incandescent illumination were obtained from the as-deposited and annealed films. Results from this characterization work are presented and discussed. Although the efficiency of nanodipole PV material structures, based on this material remains of no practical interest, our initial results indicate a possible path for the implementation of the nanodipole PV concept.