Tin doped indium oxide thin films: Electrical properties

Abstract

Tin doped indium oxide (ITO) films are highly transparent in the visible region, exhibiting high reflectance in the infrared region, and having nearly metallic conductivity. Owing to this unusual combination of electrical and optical properties, this material is widely applied in optoelectronic devices. The association of these properties in a single material explains the vast domain of its applicability and the diverse production methods which have emerged. Although the different properties of tin doped indium oxide in the film form are interdependent, this article mainly focuses on the electrical aspects. Detailed description of the conduction mechanism and the main parameters that control the conductivity is presented. On account of the large varieties and differences in the fabrication techniques, the electrical properties of ITO films are discussed and compared within each technique.

Fully Solution-Processed Semitransparent Organic Solar Cells with a Silver Nanowire Cathode and a Conducting Polymer Anode

“…-1 at 90 % transparency. 1 ITO, however, suffers from several drawbacks that limit its viability as a TCE for next-generation optoelectronics, including high cost, poor performance on plastic substrates, and a tendency to crack when flexed. 2,3 Potential solution-processable alternatives to ITO include carbon nanotubes, 4,5 graphene, [6][7][8][9] conducting polymers, 10,11 and metal nanowires [12][13][14][15] Single-Walled Carbon Nanotubes (SWCNTs) are attractive TCE materials due to their high intrinsic conductivity and mechanical durability but, owing to large inter-tube resistances, their reported performance characteristics are significantly worse than ITO.…”

Effect of ambient combinations of argon, oxygen, and hydrogen on the properties of DC magnetron sputtered indium tin oxide films

“…For example, initial reports provided a preliminary investigation into the use of an Ar+O 2 +H 2 ambient mixture, which was suitable for producing high-quality (lowest sheet resistance and high optical transmittance) of ITO films. 15,17 To build on this promising preliminary work and develop deeper insight into the effect of ambient atmospheres on ITO film growth, this study provides a more detailed investigation of the effects of ambient combinations of Ar, O 2 , H 2 on sputtered ITO films. Magnetron sputtered ITO films are deposited under the Ar, Ar with O 2 , and Ar with O 2 and H 2 (oxy-hydrogen) ambient combinations and characterized for structural, electrical and optical properties.…”

“…14 Among the various methods, magnetron sputtering is most often used by industry to fabricate commercial optoelectronic devices. 15 Magnetron sputtering enables control of the electrical and optical properties of the films through different process parameters such as sputtering pressure, sputtering power, substrate temperature, discharge voltage and ambient gases. 15,16 Among these parameters, the ambient gases are important parameters that determine the electrical and optical properties of the ITO films, but have only been given only precursory evaluation in the literature.…”

“…11,15,16 Normally the ITO films are sputtered with O 2 ambient and annealed at H 2 ambient to enhance the surplus oxygen in the ITO films. The oxygen vacancies (and thus oxygen concentration) are believed to be responsible for the lowering resistivity and increasing optical transmittance in the ITO films.…”

Thermal Effect on Characteristics of IZTO Thin Films Deposited by Pulsed DC Magnetron Sputtering

“…A free electron acting as a carrier in Sn doped In 2 O 3 is caused by two types of donors: a native defect such as oxygen vacancies and a Sn 4+ ion substituting for In 3+ . 9,10 In the case of a low deposition temperature from RT to 100 o C, oxygen vacancies due to a change in stoichiometry would contribute as an electrical charge carrier. Furthermore, the creation of free electrons from singly charged Sn In is another source for the increase in charge concentration in the IZTO films.…”