Deposition of heterostrucures of SnO2 and TiO2 by dip-coating using a two phase technique

Abstract

Considering that thin films have a variety of applications, in various areas and technologies, several ways to made them have been developed, either by physical deposition processes such as epitaxial growth, resistive evaporation, CVD (Chemical Vapor Deposition) and ALD (Atomic Layer Deposition); as chemical routes, such as sol-gel (dip-coating, spin-coating and doctor-blade) or Langmuir-Blodgett methods. Among these techniques, the sol-gel methods present simplicity in the production of oxide films, being interesting to obtain the films both in industrial scale and for scientific research. In this project the goal is to study the effects and possible advantages and disadvantages of dip-coating deposition in two-phase systems, applying this method to obtain TiO2 films and SnO2 films as well as heterostructures composed by both oxide semiconductors. The existing literature on these materials gives us a broad basis on which to work. This work aims to develop a method that shall allow larger control over the properties of the final film obtained after deposition. The proposal involves the control of parameters such as solvent choice, composition and concentration of the phases, viscosity, pH, rate of deposition, type of substrate, among others. The study of the effects of this method on the electrical and structural characteristics of the crystalline matrix are unprecedented, and shall lead to possible results not accessible with the usual method, such as improvements in the applications in areas of gas sensing, with better surface manipulation, and also for transparent electronic devices such as field effect transistors (FETs) and capacitors. (AU)