Spectral ellipsometry of La1-xMnO3 films with different degree of epitaxy

The dependence of the optical spectra of La1-xMnO3 films on the degree of epitaxy was investigated. Films of La1-xMnO3-δ (x ≈ 0.1) were grown by metal organic chernical vapor deposition on SrTiO3 and Al2O3 (r-plane cut) substrates. The films are supposed to possess a different degree of epitaxy because of various matching conditions between substrate and film lattices. The optical spectra were obtained in the range 0.5-5.0 eV by spectroscopic ellipsometry technique making use of photometric ellipsometer. Fine structure in the spectra of pseudodielectric function is discussed taking into account the excitations of Drude-type free electrons along with the charge-transfer 2 p(O) → 3d(Mn) and dipole-forbidden d-d(Mn3+) transitions. In this model the difference in the spectra of two type samples with different degree of epitaxy was considered

Growth of Ru and RuO2 films by metal-organic chemical vapour deposition

We have prepared RuO2 layers by metal organic chemical vapour deposition using liquid delivery source and by thermal evaporation of powder precursors. The films were prepared on silicon and r-plane cut sapphire substrates. We discuss thermodynamics of both types of MOCVD techniques. Liquid delivery source technique using diglyme solvent results in deposition of metallic Ru film with some traces of RuO2, while films prepared by thermal evaporation of powder precursors consist of pure RuO2 phase. Thermal evaporation MOCVD grown RuO2 films exhibit excellent electrical properties ; room temperature resistivity of 30 µΩ.cm and residual resistivity ratio between 8 and 30

Growth and characterization of LaMnO3/SrTiO3 bi-layer

We report about LaMnO3/SrTiO3 bi-layers deposited by using injection metal-organic chemical vapour deposition (MOCVD). We have studied structure of the bi-layers by X-ray diffraction and its surface by AFM. Properties of the LaMnO3/SrTiO3 interface in fabricated LaMnO3/SrTiO3/Au tunnel junction were investigated by tunneling measurements. Obtained results are discussed with regard to suitability of MOCVD grown SrTiO3 film as a matenal for tunnel junction barrier

Substrate dependent growth of highly conductive RuO2 films

We have prepared thin RuO2 films by thermal evaporation metal organic chemical vapour deposition on r-plane Al2O3, MgO, LaAlO3 and SrTiO3 single crystal substrates. The films were grown at deposition temperature TD = 500 °C. X-ray diffraction analysis show different type of preferred growth, depending on a substrate. Atomic force microscopy revealed typical surface morphology for each type of substrate. Room temperature resistivity of the films on various substrates varied between 30 and 40 µΩcm. The best parameters were obtained for epitaxialy grown RuO2 film on the r-plane cut Al2O3 substrate with a room temperature resistivity about 30 µΩcm and residual resistivity ratio (resistivity ratio between room temperature and 4.2 K) close to30