Solution combustion is an exciting phenomenon, which involves propagation of self-sustained exothermic reactions along an aqueous or sol–gel media. This process allows for the synthesis of a variety of nanoscale materials, including oxides, metals, alloys, and sulfides. This Review focuses on the analysis of new approaches and results in the field of solution combustion synthesis (SCS) obtained during recent years. Thermodynamics and kinetics of reactive solutions used in different chemical routes are considered, and the role of process parameters is discussed, emphasizing the chemical mechanisms that are responsible for rapid self-sustained combustion reactions. The basic principles for controlling the composition, structure, and nanostructure of SCS products, and routes to regulate the size and morphology of the nanoscale materials are also reviewed. Recently developed systems that lead to the formation of novel materials and unique structures (e.g., thin films and two-dimensional crystals) with unusual...

Solution Combustion Synthesis of Nanoscale Materials

Zinc-indium-tin oxide (ZITO) is a potential replacement for the currently used tin-doped indium oxide (ITO) as a transparent conducting oxide (TCO) for optoelectronic devices. At the present time ITO is the material of choice for the TCO layer, but the increasing cost of indium metal and the advent of new technologies will require alternative TCOs. Over the past 15 years, bulk and thin film studies have been amassed that report the electrical and optical properties of various ZITO compositions. This review will examine the reported data and demonstrate that the bulk subsolidus phase diagram can act as a guide to understanding the numerous and varied results reported for thin films.

Transparent Conducting Oxides in the ZnO-In2O3-SnO2 System

Indium tin oxide (ITO) thin films have been grown onto soda-lime glass substrates by sputtering at room temperature with various oxygen to argon partial pressure ratios. After deposition, the samples have been annealed at temperatures ranging from 100to500°C in nitrogen or in air. The structure, optical, and electrical characteristics of the ITO coatings have been analyzed as a function of the deposition and the annealing parameters by x-ray diffraction, spectrophotometry, and Hall effect measurements. It has been found that the as-grown amorphous layers crystallize in the cubic structure by heating above 200°C. Simultaneously, the visible optical transmittance increases and the electrical resistance decreases, in proportions that depend mainly on the sputtering conditions. The lowest resistivity values have been obtained by annealing at 400°C in nitrogen, where the highest carrier concentrations are achieved, related to oxygen vacancy creation. Some relationships between the analyzed properties have been...

Structure, optical, and electrical properties of indium tin oxide thin films prepared by sputtering at room temperature and annealed in air or nitrogen

Preparation and characterization of highly conducting and transparent Al doped CdO thin films by pulsed laser deposition

In doped CdO films: Electrical, optical, structural and surface properties

Amorphous indium oxide (In2O3) and 10-wt% SnO2 doped In2O3 (ITO) thin films were prepared by pulsed-laser deposition. These films were crystallized upon heating in vacuum at an effective heating rate of 0.00847 °C/s, while the evolution of the structure was observed by in situ X-ray diffraction measurements. Fast crystallization of the films is observed in the temperature ranges 165–210 °C and 185–230 °C for the In2O3 and ITO films, respectively. The crystallization kinetics is described by a reaction equation, with activation energies of 2.31 ± 0.06 eV and 2.41 eV and order of reactions of 0.75 ± 0.07 and 0.75 for the In2O3 and ITO films, respectively. The structures of the films observed here during heating are compared with those obtained upon film growth at different temperatures. The resistivity of the films depends on the evolution of the structure, the oxygen content and the activation of tin dopants in the films. A low resistivity of 5.5 × 10−4 Ω cm was obtained for the In2O3 and ITO films at room temperature, after annealing to 250 °C the resistivity of the ITO film reduces to 1.2 × 10−4 Ω cm.

Lynne Semple

Papers

Crystallization process and electro-optical properties of In2O3 and ITO thin films

Real-time in situ crystallization and electrical properties of pulsed laser deposited indium oxide thin films