Influence of gaseous annealing environment on the properties of indium-tin-oxide thin films

Abstract

The influence of postannealing in different gaseous environments on the optical properties of indiu-tin-oxide (ITO) thin films deposited on glass substrates using e-beam evaporation has been systematically investigated. It is found that the annealing conditions affect the optical and electrical properties of the films. Atomic force microscopy, x-ray diffraction, and x-ray photoemission spectroscopy (XPS) were employed to obtain information on the chemical state and crystallization of the films. These data suggest that the chemical states and surface morphology of the ITO film are strongly influenced by the gaseous environment during the annealing process. The XPS data indicate that the observed variations in the optical transmittance can be explained by oxygen incorporation into the film, decomposition of the indium oxide phases, as well as the removal of metallic In.

Effects of multiple heat treatment cycles on structure, optical and electrical properties of indium-tin-oxide thin films

“…Since there is no additional presence of In or Sn atoms in the ITO film, the increase in the mean grain size of the ITO crystallites can be ascribed to the oxygen incorporation into the film during thermal annealing in atmosphere. The incorporation process can occur through the oxidation of residual metal phase In and Sn atoms, and the absorption into oxygen-deficient oxides [17,26]. During the process, residual oxygen atoms inside the film and film-substrate interfaces, and on the top surface could diffuse and interact with both In and Sn atom in the film, thus forming ITO crystallites with better stoichiometry.…”

Tuning the reactivity of nanostructured indium tin oxide electrodes toward chemisorption

“…This reductive treatment is known to increase the material conductivity by decomposition of the top oxygen layer. 17,19 The resulting oxygen loss of the ITO surface was indeed evidenced by the decrease of the O/(In + Sn) ratio determined from XPS analysis of the ITO surface (Fig. S1, ESI †).…”

“…S1, ESI †). 19 We noticed concomitantly a decrease in the ITO film transmittance, down to complete loss of transparency for films submitted to high forming gas flow rates (i.e. 300 sccm) ( Fig.…”

“…17 An additional annealing step performed under N 2 or H 2 -based forming gas is also usually necessary to optimize the 3D ITO film conductivity by increasing the concentration of free charge carriers resulting from oxygen vacancies. 8,14,17,18 These additional annealing steps have been shown to strongly modify the surface chemical composition of ITO, 19 potentially thus affecting the chemisorption reactivity of functional molecules bearing organophosphorus moieties. One purpose of the present paper was to analyze the influence of the reductive annealing step on the surface reactivity of GLAD ITO electrodes.…”

Efficient photoluminescence from pulsed laser ablated nanostructured indium oxide films

“…From the observations, a fairly consistent picture emerges for explaining the increased film transmission up to 773 K, which is based upon oxygen incorporation and improved crystallinity. On post-deposition annealing, the oxygen incorporation occurs largely through the absorption into the oxygen deficient phase In 2 O 3−x to form In 2 O 3 [28,29]. It has been proposed that oxygen incorporation is a dominant reaction during annealing in atmosphere.…”