New method in the growth of thin films of Ag₂Se and structural study through Synchrotron radiation X-ray grazing incidence diffraction with in situ heating

Full text: In this work, we propose a new route to obtain Ag_2+xSe, which consists of a reactive sputtering method that gives rise to highly crystalline films of controlled stoichiometry in a matter of minutes. We have previously reported the development and fabrication of this new system, namely Pulsed Hybrid Reactive Magnetron Sputtering (PHRMS), which is based on a DC reactive sputtering. This method includes a fine control on the amount of selenium present in the alloy, fast growth rate, accurate control over the stoichiometry, and it is easily scalable for industrial production. It is known that Ag₂Se has two temperature-dependent phases, termed as low-temperature orthorhombic (β)-phase and high-temperature cubic (α)-phase, with the structural phase transition temperature around 133 °C. In the high-temperature phase, the selenium atoms form a body-centred cubic (bcc) packing, while the silver atoms are statistically distributed over several interstitial sites. Ag₂Se was investigated by means synchrotron radiation grazing incidence X-ray diffraction (SRGIXRD) in National Synchrotron Light Source at the Brazilian Synchrotron (LNLS)—XRD2 beamline—in Campinas, Brazil. The SR-GIXRD diffraction patterns obtained from room temperature to 300 °C and its subsequent controlled cooling to room temperature again in a controlled argon atmosphere are shown. (author)