Molecular layer deposition of indicone and organic-inorganic hybrid thin films as flexible transparent conductor

Abstract

Indicone films consisting of indium and organic aromatic linker are grown by molecular layer deposition (MLD) using diethyl[1,1,1-trimethyl-N-(trimethylsilyl)-silanaminato]-indium (INCA-1) as the indium precursor and hydroquinone (HQ) as the organic precursor. A constant growth rate typical for MLD is exhibited at temperature between 100 and 250 degrees C. The structure and the properties of the deposited thin films are analyzed using various experimental and theoretical techniques such as Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculations. Indicone films show time-dependent change upon exposure to ambient air, which is explained by adsorption of H2O. Furthermore, transparent and conducting organic-inorganic hybrid thin films are grown by applying supercycles of atomic layer deposition (ALD) of indium oxide and MLD of indicone. Structural, optical and electrical properties of the hybrid thin films can be adjusted according to the supercycle ratio. Especially, the hybrid film with 99:1 cycle ratio of indium oxide:indicone shows minimal change of electrical resistivity even after repeated bending over 100,000 cycles. Currently developed indicone-based hybrid thin films may have applications for flexible transparent conducting material.