Deposition of cadmium sulfide and zinc sulfide thin films by aerosol-assisted chemical vapors from molecular precursors

Authors: Ashfaque Ahmed MEMON, MALIK DILSHAD, Neerish REVAPRASADU, MUHAMMAD AZAD MALIK, JAMES RAFTERY, JAVEED AKHTAR

Abstract: New complexes with the general formula [M(S_2CN^nBu_2)_2] [where M = Cd^{II} (1) and Zn^{II} (2)] were synthesized and used as single source precursors to deposit thin films of cadmium sulfide and zinc sulfide by the aerosol-assisted chemical vapor deposition technique. The single crystal X-ray structures of 1 and 2 are also reported. Thermogravimetric analysis of 1 and 2 showed that both precursors decompose cleanly in a single step to produce their respective metal sulfides. The deposition of thin films was carried out on soda glass substrates in the 350--450 °C temperature range under inert conditions. The as-deposited thin films were characterized by powdered X-ray diffraction and field emission scanning electron microscopy. Thin films of CdS deposited at low temperature (350 °C) consist of densely packed granular crystallites with an average size of ca. 150 nm, while at higher temperatures (400 and 450 °C) particles with varying sizes and mixed morphologies are observed. The ZnS thin films deposited at 400 °C showed rod-like structures, whereas dense globular-like structures were obtained at 450 °C. Energy dispersive X-ray analysis was performed to study the chemical composition of the thin films.

Keywords: Thin films, AACVD, molecular precursor, single crystal/ZnS thin films

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