Transparent conductors—A status review

High transmittance CdO thin films obtained by the sol-gel method

It is well known that tin oxide is considered as one of the most important and studied materials for the fabrication of semiconductor gas sensors. Moreover, thin-film techniques seem the most suitable for the production of smart gas sensors on silicon substrates using microelectronic technologies. This paper presents a review of the different thin-film techniques for growing tin oxide gas sensors. A new deposition method with the acronym RGTO (rheotaxial growth and thermal oxidation) is also described in detail with regard to the preparation parameters. Finally, the structural and morphological characteristics of RGTO thin films and their electrical response to various gases are considered.

Classical and novel techniques for the preparation of SnO2 thin-film gas sensors☆

We studied the structural behavior and electrical transport properties of epitaxial α-SnO thin films grown on the (1012) α-Al2O3 (sapphire) substrate Hall effect measurements revealed that the epitaxial as-deposited SnO film is a p-type semiconductor In situ x-ray diffraction studies show that the α-SnO phase is metastable and will transform into SnO2 with the rutile type structure when annealed at high temperatures in air The onset of this phase transformation was observed to begin approximately at 300 °C during heating Shortly thereafter, rutile SnO2 was observed to coexist with α-SnO and intermediate products such as Sn and Sn3O4 After being annealed at temperatures above 600 °C, the film then fully transformed into the rutile SnO2 phase Our results show that the α-SnO to SnO2 structural transformation proceeds initially by the localized disproportionate redistribution of internal oxygen at low temperature, followed by the transformation of the remaining SnO phase and intermediate phases into Sn

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Oxidation and phase transitions of epitaxial tin oxide thin films on (1̄012) sapphire

This study investigated the effect of the substrate temperature on the structural, optical, morphological, and electrical properties of undoped SnO 2 films prepared by a spray deposition method. The films were deposited at various substrate temperatures ranging from 300–500 °C in steps of 50 °C and characterized by different optical and structural techniques. X-ray diffraction studies showed that the crystallite size and preferential growth directions of the films were dependent on the substrate temperature. These studies also indicated that the films were amorphous at 300 °C and polycrystalline at the other substrate temperatures used. Infrared and visible spectroscopic studies revealed that a strong vibration band, characteristic of the SnO 2 stretching mode, was present around 630 cm −1 and that the optical transmittance in the visible region varied over the range 75–95% with substrate temperature, respectively. The films deposited at 400 °C exhibited the highest electrical conductivity property.

S.R. Jawalekar

Papers

Physical properties of tin oxide films deposited by oxidation of SnCl2

The effect of heat treatment on the structural properties of electron-beam-evaporated SnO2 films

UV absorption studies of undoped and fluorine-doped tin oxide films

Preparation of a thin film of Pb3O4 by thermal treatment of PbO2 film

TaAlN thin film resistors with improved electrical properties