| Title | Thin films of cupric oxide: Crystallite size and conduction mechanism analysis |
| Publication Type | Journal Article |
| Year of Publication | 2012 |
| Authors | Ravi, S., Kaiser A. B., and Bumby C. W. |
| Journal | Materials Science Forum |
| Volume | 700 |
| Pagination | 71-79 |
| ISSN | 02555476 |
| ISBN Number | 9783037852637 |
| Keywords | Activation energy, Bulk effect, Conduction measurement, Conduction Mechanism, Crystallite size, Cupric oxide, Diffractograms, Electronic conduction, Grain size and shape, Grain size distribution, Hough transforms, Image analysis, Image analysis techniques, Instrumental contribution, Metal contacts, Nanocrystalline films, Nanocrystalline materials, Nanotechnology, Oxide films, Particle size analysis, Schottky barrier diodes, Schottky barriers, SEM image, SEM image analysis, Spatial in-homogeneity, Temperature dependent, Thermal oxidation, Thermally activated, Trap state, Valence band edges, Williamson-Hall, X ray diffractometers, XRD, XRD analysis |
| Abstract | Nanocrystalline films of cupric oxide (CuO) produced by thermal oxidation have been characterised using x-ray analysis, SEM image analysis and temperature-dependent conduction measurements. We describe in detail the x-ray diffractometer calibration, paying particular attention to a function-fitting procedure which enables accurate subtraction of instrumental contributions to the sample diffractograms. The Scherrer and Williamson-Hall models are used to calculate crystallite size and sample strain and also give some indication of spatial inhomogeneity. Image analysis techniques which can discern individual 'grains' (the circular Hough transform and the ImageJ particle analyser) were used to evaluate the grain size distribution from SEM images. An average crystallite diameter of ∼30 nm - determined by the ImageJ particle analyser - closely agrees with the various XRD analysis approaches. Electronic conduction in our samples is found to proceed via thermally activated transport, which we attribute to the presence of a well-defined trap state that lies ∼0.2 eV from the valence band edge. The voltage-dependence of the activation energy additionally shows that the activation is a bulk effect and not due to Schottky barriers between the sample and the metal contact. © (2012) Trans Tech Publications, Switzerland. |
| URL | http://www.scopus.com/inward/record.url?eid=2-s2.0-80053968858&partnerID=40&md5=7a101cb5ce277f43f8c1cc547f0914f3 |
| DOI | 10.4028/www.scientific.net/MSF.700.71 |
