Papers by Kuppusami Parasuraman
Metal-doped molybdenum nitride films for enhanced hydrogen evolution in near-neutral strongly buffered aerobic media
Electrochimica Acta
Abstract A series of molybdenum nitride films, viz., Mo3N2, Ag-Mo3N2, V-Mo3N2 and Cu-Mo3N2 have b... more Abstract A series of molybdenum nitride films, viz., Mo3N2, Ag-Mo3N2, V-Mo3N2 and Cu-Mo3N2 have been fabricated by magnetron co-sputtering technique and evaluated as HER electrocatalysts in near-neutral pH (pH 5) buffer medium. An optimal HER activity has been observed at about 1.8 M phosphate buffer with Cu-Mo3N2 showing highest activity. Under strongly buffered and oxygen saturated conditions the molybdenum nitride films have consistently shown very high HER selectivity in the presence of oxygen. The stability of the molybdenum nitride films has been enhanced retaining almost 100% of the initial activity in a durability test, whereas, a significant loss in the stability has been observed for the same catalysts in 0.5 M H2SO4 solution.
Highly crystalline methylammonium lead iodide films: Phase transition from tetragonal to cubic structure by thermal annealing
Journal of Vacuum Science and Technology, 2021
Herein, a very simple, solvent free, scalable, and single-step approach to prepare organometal ha... more Herein, a very simple, solvent free, scalable, and single-step approach to prepare organometal halide perovskite powders via mechanochemical synthesis followed by the deposition of perovskite films by spin coating is reported. This work particularly deals with various parameters that influence the crystallization process and morphology (hyperbranched) of methylammonium lead iodide films. Moreover, the influence of growth temperature on the morphology and the transition from tetragonal to cubic structure are investigated. The mechanosynthesized perovskite provides hyperbranched morphology and crystalline films in a hexagonal shape and serves as a better precursor for the absorber layer in perovskite solar cells.
Residual stress measurements in electron beam evaporated yttria doped zirconia films deposited on Si (111) substrates
Journal of Vacuum Science and Technology, 2018
Zirconia thin films with varying yttria concentrations (0, 4, and 10 mol. %) were grown on Si (11... more Zirconia thin films with varying yttria concentrations (0, 4, and 10 mol. %) were grown on Si (111) substrates using electron beam physical vapor deposition technique. The residual stress as a function of depth on undoped and yttria doped zirconia films with different phases was determined using the modified sin2ψ technique by varying the x-ray angle of incidence. Surface profilometry was also used as a complementary technique for qualitative measurement of stress in these films. The residual stress profile revealed that tensile residual stress was present in the near-surface region and it decreased rapidly as a function of depth in all three films with different yttria concentration. The possible reasons for the film growth stress and stress gradient in the yttria doped zirconia films with different concentration of yttria are discussed.
Optoelectronic and electrochemical behaviour of γ-CuI thin films prepared by solid iodination process
Progress in Natural Science: Materials International
Role of copper/vanadium on the optoelectronic properties of reactive RF magnetron sputtered NiO thin films
Applied Nanoscience
Highly transparent zinc nitride thin films by RF magnetron sputtering with enhanced optoelectronic behavior
Materials Science and Engineering: B
Advanced Materials Research, 2010
Zr-N thin films were deposited on Si (100) substrate by reactive sputtering using a pulsed DC mag... more Zr-N thin films were deposited on Si (100) substrate by reactive sputtering using a pulsed DC magnetron sputtering technique. It was found that films deposited at 773 K and 1 sccm of nitrogen flow rate show a single phase with face centred cubic-ZrN. Raman analysis also confirmed the formation of ZrN phase in the films. The films deposited at nitrogen flow rate greater than 1 sccm show ZrN along with orthorhombic-Zr 3 N 4. The chemical bonding characteristics of the films were analyzed by X-ray photoelectron spectroscopy. High resolution transmission electron microscopy also gave evidence for fcc-ZrN and o-Zr 3 N 4 phase and revealed equiaxed grains in these films. In addition, hardness and Young's modulus of the films measured as a function of nitrogen flow rate is discussed qualitatively in relation to resistance to plastic deformation offered by these films.
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Papers by Kuppusami Parasuraman