Morphological Reaction on the Different Stabilizers of Titanium Dioxide Nanoparticles

Three different stabilizers have been chosen for TiO2 solution preparation via sol-gel method to form a resistive sensor. TiO2 solution was prepared by mixing of ethanol as a solvent, titanium isopropoxide as a precursor and hydrochloric acid (HCl) as a stabilizer thus synthesis pH 1 aqueous solution. These TiO2 solution preparation steps were repeated by replacing HCl with another catalysts which are acetic acid (AA) (pH 3.05) and monoethanolamine (MEA) (pH 10.4) for the second and third TiO2 solution preparation respectively. Spin-coating technique was used to uniformly deposit TiO2 film on silicon dioxide substrate. The deposited thin films were then annealed at various temperatures (400, 500, 600, 700 and 900 oC) for 30 min using annealing furnace. Finally, aluminum metal was deposited on the TiO2 film and simple lithography method was used to fabricate electrodes. The X-ray diffraction (XRD) exhibits rutile structures are more favorable to grow on TiO2 film synthesis with acidic solution (pH 1 and pH 3.05) even at very low temperature. Otherwise, base-solution of TiO2 tends to synthesis anatase phase at low and average temperatures. While field emission scanning electron microscopy (FESEM) was used to observe the crystallite form also reconfirmed the crystallite size growth. The relation between film roughness, thicknes are correlated with the pH level were confirmed by atomic force microscopy (AFM). The electrical current flow through these samples with fixed voltage applied were measured and it shows the smallest current flow between the fabricated fingers is 0.96 nA which is from the lowest pH level of HCl.