Structural and optical properties of as-grown and annealed Alq3 thin films

International audienc

Optical and structural characterization of thin films containing metallophthalocyanine chlorides

Abstract The structural and optical investigation of thin films containing aluminum and gallium phthalocyanine chlorides is presented. The films were fabricated by Physical Vapor Deposition technique onto quartz substrates and annealed after fabrication in an ambient atmosphere for 24 h at the temperature equal to 150 °C or 250 °C. The experimental results and theoretical calculation of the Third Harmonic Generation process are reported. The third order nonlinear optical properties are expected and can be more or less accurately predicted due to the assembly of the molecules and theoretical calculations of the frequency-dependent dipole polarizabilities, third hyperpolarizabilities, third order susceptibilities, frontier and second frontier molecular orbitals. These parameters were used to understand the relationship of optical properties with the molecular structures. We found that the annealing process causes formation of nanostructures and the value of the third order optical susceptibility makes these materials interesting for future nonlinear optical applications

NLO investigations of self-assembled organometallic thin films

This work contains investigation results of the structural and nonlinear optical properties of self-assembled organometallic thin films. The films were successfully grown by Physical Vapor Deposition technique in high vacuum on transparent (quartz, glass) and semiconductor (n-type silicon) substrates kept at room temperature during the deposition process. Selected films were undergone an annealing process in ambient atmosphere for 24 hours in order to observe the process of self-organization. Nonlinear optical properties were examined using Second and Third Harmonic Generation\u27s techniques. The experimental spectra allowed determining optical constants of the films. Structural properties and self-assembling process were investigated by AFM and XRD measurements. The films exhibit very interesting structural properties strongly dependent on the temperature of the annealing process. NLO properties of self-assembled organometallic thin films were strongly related with the morphology and the annealing process can significantly change the structure of the organometallic films

Photophysical properties of Alq3 thin films

This work contains investigation results of the photophysical properties of aluminum (III) tris(8-hydroxyquinoline) thin films. The Alq3 thin films were successfully fabricated by Physical Vapor Deposition technique. The films were grown on transparent: (quartz and glass) and semiconductor (n-type silica) substrates kept at room temperature during the deposition process. Selected films were annealed after fabrication in ambient atmosphere for 12 h at the temperature equal to 100 °C and 150 °C. Morphology of the films was investigated by AFM technique. Photophysical properties were characterized via photoluminescence, transmission, second and third harmonic generation measurements. The thin films exhibit high structural quality regardless of the annealing process, but the stability of the film can be improved by using an appropriate temperature during the annealing process. Photoluminescence of Alq3 films obtained in air were efficient and stable. The measurements of transmission, SHG and THG spectra allowed us to determine optical constant of the films. We find that the photophysical properties were strictly connected with the morphology and the annealing process significantly changes the structural properties of the films

Photoluminescence studies of selected styrylquinolinium thin films made using thermal evaporation deposition technique

In this paper we present a photoluminescence (PL) study of new styrylquinolinium dyes. We made a comparative study of the luminescent properties of thin films grown on quartz substrates using thermal evaporation deposition method. Investigated films show PL emission from the violet to near-IR region at room temperature

Silicon microelectronics: where we have come from and where we are heading

The paper briefly presents the history of microelectronics and the limitations of its further progress, as well as possible solutions. The discussion includes the consequences of the reduction of gate-stack capacitance and difficulties associated with supply-voltage scaling, minimization of parasitic resistance, increased channel doping and small size. Novel device architectures (e.g. SON, double-gate transistor) and the advantages of silicon-germanium are considered, too

Arbitrary waveform generator for charge-pumping

The paper presents a new signal generator for charge-pumping. Modular structure of the generator is discussed with special emphasis on signal-generation module consisting of five independent signal channels. Digital signal synthesis is chosen to minimize inaccuracies. Noise analysis is performed to demonstrate the validity of the design of signal channel. Calibration procedure is also discussed

MÖSSBAUER SPECTROSCOPY STUDIES OF POLYACETYLENE DOPED CHEMICALLY AND ELECTROCHEMICALLY WITH IRON CHLORIDES

Le dopage du polyacétylène avec les complexes chlorure de fer a été étudié par spectroscopie Mössbauer. On a prouvé que le polymère dopé est soumis à la dégradation à l'air avec la formation de FeCl2nH2O et la chloruration simultanée de la liaison double.Doping of polyacetylene with iron chloride complexes has been studied by Mössbauer spectroscopy. It was proved that the doped polymer undergoes degradation in air manifested by the formation of FeCl2nH2O with the simultaneous chlorination of the double bond

Deep Level Studies in Zn1−x\text{}_{1-x}Mgx\text{}_{x}Se Layers Grown by MBE

The deep levels present in semiconducting Zn$\text{}_{1-x}$Mg$\text{}_{x}$Se (0 ≤ x ≤ 0.4) were investigated by means of deep level transient spectroscopy, photocapacitance transient and thermally stimulated depolarization. The thermal activation energy levels estimated from the deep level transient spectroscopy measurements are: E$\text{}_{T1}$=0.28 eV and E$\text{}_{T2}$=0.56 eV. For the Zn$\text{}_{1-x}$Mg$\text{}_{x}$Se epilayers thermally stimulated depolarization curves consist of four overlapping peaks: 227.4 K, 243.6 K, 265.7 K, and 285.0 K