Emission of Tantalum Oxide Nanocluster Thin Films at High Temperatures

Abstract

The results of the formation, certification of the surface morphology and chemical composition, as well as the results of the study of radiation upon heating to high temperatures (600–800°C) of Ta₂O₅ nanocluster films obtained by sputtering a Ta target in an atmosphere of Ar and O2 gases with subsequent filtering of the formed clusters according to the selected sizes and their deposition on a metal substrate (Ta). Surface images were obtained by atomic force microscopy (in situ) and it was shown that Ta films have a loose structure consisting of close-packed spherical nanopPicles. XPS analysis of the chemical composition showed that the resulting films are of high purity and are close to the Ta₂O₅ compound. Using a spectrometer with a working range of 600–1700 nm, the emission spectra of films and substrates with natural tantalum oxide were obtained when heated to various temperatures. It is shown that films with small cluster sizes (2–3 nm) have a more stable emissivity at varying temperatures than films with large clusters (4–5 nm). In addition, when heated to the same temperature, small tantalum oxide clusters radiate more efficiently than a substrate with natural tantalum oxide film. The question is raised about the prospects of using the obtained structures as part of selective emitters to improve the efficiency of thermophotovoltaic systems.