| Abstract
| - A novel method for the vacuum deposition of thin fluorescent dye coatings by means ofglow discharge induced sublimation (GDS) is disclosed. Powdered organic compound is puton a radio frequency plasma sputtering source and bombarded by low energy (<1 keV) noblegas ions and electrons. Ion bombardment gives rise to a local heating which inducessublimation of the dye molecules. The method has been successfully used for deposition of3-hydroxyflavone (3-HF) coatings on silicon substrates. Plasma diagnostics, as performedby means of mass spectrometry and in situ optical emission spectroscopy, point out boththe sublimation of integer 3-HF molecules and the presence of 3-HF molecular fragmentsin the glow discharge. The integer 3-HF molecules are positively ionized or protonated beforereaching the substrate. Rutherford backscattering spectrometry and elastic recoil detectionanalysis confirm that the deposited film is stoichiometric within the experimental errors.FT-IR analysis points out all the main characteristic peaks reported in the literature forpure 3-HF. Fluorescence analysis shows that the spectroscopic properties of 3-HF arepreserved after the deposition process, despite the gas-phase ionization and protonation ofthe molecules. In particular, the emission features are typical of molecules embedded in anapolar and aprotic environment.
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