Structural, optical, and dielectric properties of sol-gel derived SrTiO3 thin films

Abstract

Articles you may be interested inEffect of sol-age on the surface and optical properties of sol-gel derived mesoporous zirconia thin films Transparent and crackfree SrTiOs thin films were deposited on silicon wafers, fused silica, and stainless-steel substrates by sol-gel technique. Strontium ethyl hexanoate and titanium isopropoxide were used as starting materials. The surface topology of the films were studied by electron micrography and the structural properties by x-ray diffraction. The refractive index and band gap were measured by optical transmission and absorption spectroscopy. The films show very low leakage current and nearly temperature independent dielectric constant at high frequencies. The dielectric constant and loss factor at 1 kHz at room temperature were 131 and 0.022, respectively. The frequency dependent ac conductivity has been explained on the basis of potential barriers formed by the charge carriers trapped at intercrystalline regions.

Structure and Optical Properties of SrTiO3 Thin Films Prepared by a Sol–Gel Technique

“…The band gap E g of thin films can be obtained by extrapolating the linear portion of the plot relating ahn 2 and hn to ahn 2 0. The value for SrTiO 3 thin film annealed at 700 C is 3.47 eV, which is a little larger than that of the single crystal 3.37 to 3.41 eV reported [19] and that of the sol±gel-derived thin film 3.43 eV reported elsewhere [4]. It is believed that the difference of band gap between the well-crystallized film and the crystal is due to the existence of grain boundaries in the polycrystalline thin films.…”

“…Besides, SrTiO 3 thin films are chemically and compositionally very stable and have excellent optical transparency which make them excellent insulating layers for limiting current in thin film electroluminescent displays (TFELs) [3,4].…”

Tensile strain induced changes in the optical spectra of SrTiO3 epitaxial thin films

“…In most cases, the band-gap energies of poor-crystallized films with pronounced interlayer effects appear to be larger than those of single crystals (e.g. [8,12,15]), although it is not always the case [9], The bandgap of highly crystallized films appears to be at least comparable to that of single crystals [10,14,15]. To our knowledge, optics of sufficiently high nanometric quality of STO films was studied in [13] (polycrystalline films on silica targets) and [14] (homoepitaxial, metallic, oxygen-deficient STO films on STO substrates) in which no conspicuous band edge shift has been found.…”

“…Only few studies were devoted to basic optical characteristics of STO thin films, such as refractive index and band edge optical transitions (e.g. [8][9][10][11][12][13][14][15][16][17]) controlling principal photoelectronic properties. Even so, these studied have been performed with thin films of different quality, polycrystalline (or different degree of crystallinity), and/or amorphous films, deposited by various techniques on various substrates with pronounced films-substrate interfacial layers, imperfections etc.…”

Dielectric Properties of Tungsten Oxide Thin Film Prepared by Spray Pyrolysis

“…The increase in tan d especially at higher temperature and in the low-frequency region is presumably due to the increase in the number of free carriers thermally generated. Such behaviour is also observed in SrTiO 3 thin films [17] and insulating films [18,19]. Fig.…”