In this dissertation, solid solutions of indium-iron oxide (In_2-xFe_xO₃) with varying compositions were prepared and a new ultra-fast microwave method was used for deposition of thin films of this material. Non-destructive characterization methods were used for studying these transparent conducting oxide (TCO) materials.

In this work, the linear thermal expansion coefficients of bulk In _2-xFe_xO₃ have been determined using high resolution x-ray diffraction measurements. The addition of Fe₂O₃ to In₂O₃ resulted in the formation of solid solutions in body centered cubic phase. The thermal expansion coefficients for solid solutions of In_2-xFe_xO₃ showed increased values in comparison to that of pure In₂O₃ phase. The study of thermal properties of these TCO materials is crucial for their potential applications in photovoltaic and spintronic devices operating at various temperatures.

In addition, the bulk samples of In_2-xFe_xO ₃ were studied for their structural, transport, and magnetic properties, as a function of composition. The lattice parameters of the solid solutions decrease with increasing Fe-content. The four-probe electrical measurements showed reduced conductivities for higher Fe compositions. The magnetic data displayed ferromagnetism in these solid solutions, and that can be attributed to the presence of trace amounts of Fe₂O₃ or Fe ₃O₄. These results might be important for the use of TCOs in spintronic applications as well as structural materials such as ceramic coatings intended to withstand harsh environments.

Thin films of Indium-iron oxide compositions were deposited by using ultra-fast microwave heating. This is a new method of deposition of TCOs that has never been done before. The advantage of microwave heating deposition over other deposition techniques is that it is extremely fast and can be used for materials of high evaporation temperature. In this work, the deposition was done in 50-120 seconds at 1950-2000°C. Characteristics of these transparent films were consistent with those of the bulk materials as determined by x-ray diffraction techniques. These films were subjected to a very high temperature (500 to 600°C), and were found to be physically stable.

The benefits of the In_2-xFe_xO₃ TCO solid solutions may lead to their potential advantage in optoelectronic, magnetic, and structural applications. In addition, these materials offer a better stability at both low and high temperature ranges, and are structurally robust.