On the preparation of ultrathin tin dioxide by Langmuir–Blodgett films deposition

Langmuir–Blodgett (LB) technique has been used for the preparation of ultrathin tin dioxide film. Octadecyl amine (ODA) forms a stable complex with sodium stannate at the air–water interface and ODA–stannate complex has been deposited on solid substrate by LB technique. Multilayer LB films have been decomposed at 300 °C and 600 °C for 2–3 h to form thin metal oxide films on various substrates. The oxide films have been characterized by various techniques such as X-ray diffraction (XRD), Fourier transform infra-red (FTIR) spectroscopy, UV–visible spectroscopy, X-ray photoelectron spectroscopy (XPS), atomic force microscopy, scanning electron microscopy, capacitance–voltage and current–voltage measurements. XRD measurements show the formation of crystalline structure of SnO2 after heating of the multilayer LB film at a temperature of 600 °C. FTIR and XPS measurements indicate that ODA molecule is almost removed after heating at 300 °C and pure SnO2 has been formed when it is heated at 600 °C. Current and capacitance voltage measurements on Si/SnO2/gold and quartz/SnO2/gold structure show the formation of semiconducting SnO2 thin films.