Whiskers in indium tin oxide films obtained by electron beam evaporation

Abstract

Indium tin oxide thin films consisting mainly of whiskers have been deposited on glass by electron beam evaporation. Low deposition rates ͑35 Å/min͒ and substrate temperatures in the 120-400°C range were used. Morphology by scanning electron microscopy, crystal structure, energy dispersive analysis of x-rays, and x-ray photoelectron spectroscopy compositions, optical and conducting properties of films have been studied as a function of temperature of growth and further annealing in air. Whiskers associate and produce flatter surfaces, the grain size increases from Ϸ390 Å to Ϸ790 Å, keeping however its fibrous structure after 400°C-30 min annealing. In films deposited at temperatures below 200°C, next to cubic In 2 O 3 , tetragonal Sn and cubic In 2 Sn 2 O (7Ϫx) appear. During growth and after air annealing Sn 4ϩ segregates to the surface, attaining Sn/In concentration ratios of 4.6. On air annealing the optical transmittance and electrical resistance increase, in some cases from 2% to 90% and by a factor of about 4, respectively.

In2O3 and tin-doped In2O3 nanocrystals prepared by glass crystallization

“…The effect of tin incorporation into the In 2 O 3 lattice has already been discussed in [12][13][14][15]. As shown by X-ray photoelectron spectroscopy [13] on thin films, tin is solely incorporated as Sn 4+ .…”

“…With increasing tin concentration, the lattice constant increases again. According to [13,14] this suggests the incorporation of Sn 4+ in interstitial sites. It should be noted that according to [13], the electric conductivity as well as the charge carrier concentrations of thin films increases strongly up to 11 mol% SnO 2 .…”

Properties of an Indium Tin Oxide Electrode Modified by a Laser Nanostructured Thin Au Film for Biosensing

“…For the investigated structures, in frames of the Drude model it is the SPR resonance linewidth that represents the measure of damping γ of the free-electron oscillations in the isolated Lorentz spherical cavity, with the dielectric function given by Equation (5). (5) ω p = ne 2 /m e is the plasma oscillation frequency of the electrons, with the free electron density n, the electron charge e and effective mass m e , and γ is the damping constant of electron motion. For bulk metals γ = γ bulk is related to the electrical resistivity of the metal and is supposed to include all microscopic damping processes arising from photons, phonons, impurities, and electron-electron interactions.…”

“…[5] The application range of ITO covers optoelectronic devices such as organic light-emitting diodes, [13,14] solar cells, [15] and sensitive detectors dedicated to glucose, [16] hydrogen peroxide, [17] or DNA fragments. [18] The application capability of transparent conductive oxide materials stimulate increased research activity in this area and the growing commercial scale production observed recently.…”

“…The ITO substrate is known for its high electrical conductivity, low capacitive current, electrochemical activity over a wide potential range, and stable physical and electrochemical properties. [4] However, these properties depend on the fabrication method applied, such as e-beam evaporation (EBE), [5] the spray pyrolysis, [6] chemical vapor deposition (CVD), [7] sol-gel, [8] laser ablation, [9] and DC [10] and RF sputtering. [11,12] Also the fabrication conditions influence the ITO properties, e.g.…”