Preparation of SnS films using solid sources deposited by the PECVD method with controllable film characters

Abstract

Although the fabrication of SnS films by plasma-enhanced chemical vapour deposition (PECVD) has been reported by many researchers, to date there is no report available on the preparation of SnS films from solid source materials through the PECVD method. In the present work, SnS films are deposited from cost-effective and low-toxicity source materials (SnCl 2· 2H 2O and Na 2S 2O 3·5H 2O) by a modified version of the PECVD technique. The X-ray diffraction (XRD) patterns demonstrate that the SnS films are successfully prepared. The field-emission scanning electron microscopy (FESEM) images reveal that the morphologies of the SnS films present mixed morphological features in accordance with the XRD results. The energy dispersive X-ray (EDX) analysis reveals that the stoichiometric ratios of the obtained SnS films are approximately the standard value of SnS, with slight deviations. The Raman spectra show that the Raman modes for the obtained SnS films are observed at 82, 109, 166, 195 and 226 cm -1. The optical properties are studied by UV-Vis-NIR spectrophotometry, and the results demonstrate that the optical band gap of the SnS film deposited on the soda-lime glass microscope slides is 1.5 eV. The absorption coefficient α is larger than 10 4 cm -1 in the photon energy range of 0.5-4 eV. Moreover, the morphology of SnS films changes with the deposition parameters, and a plate-like morphology can be deposited when the deposition temperature is decreased. Therefore, high-quality SnS films can be deposited by PECVD from solid source materials, and the distinct surface morphologies of the films can be attributed to the controllability of the PECVD deposition system. © 2012 Elsevier B.V. All rights reserved.