Optical and gas sensing studies of transparent ZnO thin film deposited from a new precursor by ultrasonic aerosol assisted chemical vapor deposition

Abstract

Transparent semi-conducting ZnO thin films with low resistivity and high transmittance in the visible optical region were deposited by the decomposition of bis(2,4-pentanedionate)-bis(aminoethanol) zinc(II) under an atmosphere of oxygen on ceramic, metal and quartz substrates by ultrasonic aerosol assisted chemical vapor deposition. The precursor was synthesized from bis(2,4-pentanedionate) zinc(II) and aminoethanol by sonication in acetonitrile and was characterized by melting point, infrared spectroscopy, CHNS-O elemental, atomic absorption, and single crystal X-ray diffraction analysis. TGA-FTIR was used to identify the cause of the weight losses and evolved gases formed during the breakup of the molecules. Electrical and optical measurements showed that the ZnO film has a band gap of 3.02 eV and typical semiconductor properties with a resistivity that depends on the thickness of the film. Powder XRD, SEM and EDX show that films are uniform, smooth and crystalline in nature, giving particle sizes in the range of 30-60 nm and exhibit a (002) orientation with the c-axis perpendicular to the substrate surface.