The room temperature, photoluminescent properties of manganese‐doped zinc sulfide films deposited by spray pyrolysis are reported. These films were deposited on Pyrex glass substrates at atmospheric pressure using air as a carrier gas. All films were polycrystalline with a wurtzite (hexagonal) structure. The manganese doping was achieved by mixing MnCl₃ with the starting solution to deposit ZnS. The photoluminescence spectra was measured at room temperature as a function of the different deposition parameters and the Mn concentration. Besides the characteristic light emission associated with Mn impurities in a ZnS matrix, a peak associated with the self‐activated emission was also observed under certain deposition conditions (low substrate temperatures and/or long deposition times). The presence of chlorine impurities in the films is suggested to be associated with this emission. The Mn luminescence presents a quenching effect with the Mn concentration. This quenching effect is similar to the one reported on films deposited by other techniques. The light emission at this center has an activation energy of 0.71±0.05 eV with the deposition temperature. This energy is proposed to be related with the energy required by the Mn atoms to find a proper site during the growth process to form a Mn²⁺ center.

The spray pyrolysis technique has been extensively used to synthesize materials for a wide variety of applications such as micro and sub-micrometer dimension MOSFET´s for integrated circuits technology, light emitting devices for displays, and solid-state lighting, planar waveguides and other multilayer structure devices for photonics. This technique is an atmospheric pressure chemical synthesis of materials, in which a precursor solution of chemical compounds in the proper solvent is sprayed and converted into powders or films through a pyrolysis process. The most common ways to generate the aerosol for the spraying process are by pneumatic and ultrasonic systems. The synthesis parameters are usually optimized for the materials optical, structural, electric and mechanical characteristics required. There are several reviews of the research efforts in which spray pyrolysis and the processes involved have been described in detail. This review is intended to focus on research work developed with this technique in relation to high-K dielectric and luminescent materials in the form of coatings and powders as well as multiple layered structures.

The optical and electrical characteristics of spray pyrolysis deposited aluminum oxide films are reported. The films were deposited from a spraying solution of aluminum acetylacetonate in $\mathrm{N,N}$ -dimethylformamide using an ultrasonic mist generator on (100) Si substrates. The addition of water mist during the spraying deposition process resulted in an overall improvement of the films characteristics. The substrate temperature during deposition was in the 450–650 °C range. Deposition rates up to 90 Å/s were obtained depending on the spraying solution concentration and substrate temperature with an activation energy of the order of 31 kJ/mol. The optical energy band gap for these films was 5.63 eV and the refractive index at 630 nm up to 1.66 was measured by ellipsometry. The electrical characteristics of the films were determined from the capacitance and current versus voltage measurements of metal–oxide–semiconductor (MOS) structures incorporating them. A dielectric constant of 7.9, interface states density of the order of ${10}^{11}\text{×1/}{\mathrm{eV\hspace{0.17em}cm}}^{\mathrm{2}}$ as well as breakdown fields higher than 5 MV/cm were determined in this way.

The electrical characteristics of off‐stoichiometric silicon dioxide films have been investigated. The off‐stoichiometric oxide films studied had an excess atomic silicon (Si) content in the range of 1%–6%. Raman spectroscopy and photoconductivity measurements indicate that the excess Si is present as amorphous Si islands or small crystallites embedded in silicon dioxide (SiO₂) forming a two‐phase material. These films differ in structure from previously reported films where dual dielectric layers of stoichiometric SiO₂ and Si‐rich SiO₂ with ≥13% excess atomic Si were used. These dual dielectric films were observed to produce electron injection from contacting electrodes via the Si‐rich SiO₂ layer into the SiO₂ at lower average electric fields. This injection mechanism was believed to be due to localized electric field enhancement near the SiO₂–Si‐rich SiO₂ interface caused by the curvature of the tiny Si islands in the SiO₂ matrix. The current versus voltage characteristics of the off‐stoichiometric oxide films which will be discussed here were found to be highly nonohmic, showing an increase in conductivity with increasing excess silcion content in the material. At low fields (≲1 MV/cm), these films have a very small conductance with leakage current densities smaller than 10⁻¹¹ A/cm² at room temperature. Furthermore, the effect of permanent charge trapping was observed to decrease in these films with increasing Si content. It is proposed that the electron transport across the film is controlled primarily by tunneling between the silicon islands with a reversible space charge region ≲150 Å in extent near the injecting contact, limiting the current measured in the external circuit. It is also proposed that the decrease in permanent electron trapping is associated with this conduction mechanism and/or the possibility of trapped electrons in the SiO₂ phase tunneling to the Si islands. With the incorporation of these off‐stoichiometric oxides into electrically‐alterable read‐only‐memory devices, extended write/erase cycling (by at least four orders of magnitude) beyond that normally observed for equivalent devices using stoichiometric SiO₂ layers is demonstrated due to the reduction in permanent electron trapping in the oxide layer and its effect on the electric fields.