Giedrius Laukaitis

SILAR deposition of CdxZn1-xS thin films

Abstract Cd x Zn 1− x S thin films were grown on (100)GaAs by the successive ionic layer adsorption and reaction (SILAR) technique from dilute aqueous precursor solutions. Crystallinity, refractive index and morphology of the thin films were studied as a function of composition and thickness of the films. The Cd x Zn 1− x S films were polycrystalline and cubic. The crystallite size and refractive index of the films increased when the film thickness and Cd concentration in the Cd x Zn 1− x S thin films increased. It was found that tensile stress dominates in thin films when Cd concentration is lower than x ≤0.54 and the change of the residual stress to the compressive one takes place after that. Correlation between the growth mode and residual stress is demonstrated.

Growth of PbS thin films on silicon substrate by SILAR technique

Lead sulfide thin films were grown on (100)Si and (111)Si crystalline substrates by successive ionic layer adsorption and reaction, (SILAR), technique from solution phase at room temperature and normal pressure. The stress development, crystallinity and crystallite size, morphology and roughness and composition of the films were characterized as a function of the film thickness. The PbS thin films were polycrystalline and cubic. The residual stress in PbS was tensile and changed depending on the growth mode and thickness of the PbS films.

Stress and surface studies of SILAR grown ZnS thin films on (100)GaAs substrates

Zinc sulfide thin films were grown on (100)GaAs by the successive ionic layer adsorption and reaction (SILAR) technique from dilute aqueous precursor solutions. The stress of thin films was characterized by means of laser interferometry, crystallinity by X-ray diffraction, refractive index by ellipsometry and by fitting the reflectance spectrum, composition by electron spectroscopy and morphology by atomic force microscopy. A clear correlation between the growth mode and the residual stress level is demonstrated. The changes from three-dimensional to two-dimensional growth of the film results in the change of the residual stress from tensile to compressive. The films were polycrystalline and cubic with rather low crystallinity. The crystallite size and the refractive index of the films increased when the film thickness increased.

Stress and surface studies of SILAR grown CdS thin films on GaAs(100)

Abstract Cadmium sulfide thin films were grown on GaAs (100) by the successive ionic layer adsorption and reaction (SILAR) technique from aqueous precursor solutions. The purpose of this work was to analyze and find stress dependence of CdS thin films thickness and growth mode. The stress of the thin films was characterized by means of laser interferometry, composition and morphology by electron spectroscopy for chemical analysis (ESCA) and by atomic force microscopy (AFM). Correlation between the growth mode and the residual stress level is demonstrated. The changes from three-dimensional to two-dimensional growth of the film results in the change from tensile to compressive residual stress (from 1.39 to −2.50)×109 N/m2.

Electronic Speckle Pattern Interferometry for micromechanical measurements

A new optical setup that could be used for the analysis of displacement (or strain) of objects with diffuse as well as mirror-like reflecting (specular) surfaces is presented here together with the algorithm of data analysis. Combination of these two new approaches allows to minimize the area of analysis and to extend the class of materials to which the Electronic Speckle Pattern Interferometry (ESPI) can be applied.

Optical measurements of strain and stress in thin films

Principles and applications of the cantilever technique to measure strain and stress in thin films are presented. Different optical interferometers were created and applied to control stress-thickness dependence during technological processes or to measure two-dimensional strain distribution in thin film. An original scheme combining advantages of the classical interferometer and electronic speckle pattern interferometer is presented.

Influence of Deposition Parameters on the Structure of TiO 2 Thin Films Prepared by Reactive Magnetron Sputtering Technique

TiO2 is well known for its photocatalytic properties and wide range of applications. However, the efficiency of amorphous TiO2 as photocatalyst is low and deposition of crystal TiO2 phases is strict to deposition parameters. The TiO2 phase dependence on temperature, total pressure (ptot) and oxygen partial pressure and total pressure (pO2/ptot [%]) ratio and how this affect growth rate has been studied in this work, TiO2 thin films were deposited via magnetron sputtering technique using different deposition parameters in order to get TiO2 either pure anatase or rutile phase. Crystallographic structure and morphology of deposited thin films were analyzed by XRD and SEM/EDS. TiO2 phase strongly depends on substrate temperature during the deposition of thin films, total pressure and pO2/ptot ratio. Analysis shows that TiO2 anatase phase depends more on substrate temperature than pO2/ptot, while TiO2 rutile phase in reverse, noting that it has better stability at high temperatures compared to anatase.

Formation and Investigation of Doped Cerium Oxide Thin Films Formed Using E-Beam Deposition Technique

The investigation of new functional materials (ceramics) based on cerium (IV) oxides is a promising field of scientific research. A wide application in the industry received composite materials based on CeO2–Gd2O3 and CeO2–Sm2O3.