ALD/MLD fabrication of luminescent Eu-organic hybrid thin films using different aromatic carboxylic acid components with N and O donors

Abstract

Atomic/molecular layer deposition (ALD/MLD) processes based on Eu(thd)₃ and three different aromatic organic acids with O and N donors as precursors are systematically investigated for the growth of Eu-based inorganic–organic thin-film phosphors. For all the acid precursors evaluated, i.e. 1,4-dicarboxylic, 3,5-pyridinedicarboxylic and 2,6-pyridinedicarboxylic acids, conditions are found to produce high-quality hybrid thin films through self-saturating gas–solid reactions as expected for an ideal ALD/MLD process. The resultant Eu-organic thin films show intense red photoluminescence. The luminescence characteristics depend on the manner the organic ligands are bound to Eu³⁺; this is discussed based on FTIR, XPS, UV-vis and fluorescence spectroscopy data measured for the films.