Multilayer Thin Film Systems Research Articles

Latent heat effects of pulsed laser beam induced temperature profiles in optical recording thin films

A numerical algorithm for the computation of the temperature profile induced by a pulsed laser beam has been developed by means of the quasi-implicit technique. In this calculation the effect of the latent heat of fusion was included in the temperature calculation. Some examples are given to demonstrate the utility of the numerical technique for calculating temperature profiles in optical recording media. The effects of various thermodynamic properties of recording media are apparent in the examples presented in this work, and the result of the calculated temperature information can be readily applied to the study of the writing mechanism. Extensions to a multilayered thin film system can be easily done simply by modifying the matrix elements which involve the interfacial layers.

Auger electron spectroscopy study on interfacial reactions in multilayer thin film systems: Kril A Pandelišev and Edward Y Wang, J Appl Phys, 53 (6), 1982, 4422–4427

Auger electron spectroscopy study on interfacial reactions in multilayer thin film systems: Kril A Pandelišev and Edward Y Wang, J Appl Phys, 53 (6), 1982, 4422–4427

Auger electron spectroscopy study on interfacial reactions in multilayer thin film systems

Interfacial reactions at room temperature in multilayer thin film systems have been investigated by the Auger Electron Spectroscopy method. The multilayer thin film structure consists of metal, native oxide, and/or deposited interfacial layers on metal and semiconductor substrates. Various combinations of metals and interfacial layers on different substrates have been investigated. For the multilayer systems Au, Ag, Cu, and Cr were used as metals, GeO2, Bi2O3, SnO2, Sb2O3, Ga2O3, and As2O3 were used as interfacial layers, and GaAs, Si, and Fe were used as substrates. Only ’metal’ atoms from the interfacial oxide layers (Ge from GeO2, Sb from Sb2O3, Bi from Bi2O3, Sn from SnO2, and Ga and As from the native oxide mixture of Ga2O3 and As2O3) were detected on the metal surface of Metal-Interfacial layer-Semiconductor and Metal-Interfacial layer-Metal-Semiconductor structures. This indicates that the interfacial reaction takes place only at the metal-interfacial layer interface. ’Drive-out’ diffusion is present at all interfacial reactions. The interfacial reactions and the drive-out diffusion processes are thought to play an important role in the degradation of thin film multilayer structures.

The Relationship between Optical Absorptance and Electric Field of the Radiation in Multilayer Thin Films

The concept of potential transmittance is used to show how the distribution of absorptance in a multilayer thin film system for the general case of radiation incident obliquely can be obtained from the reflectances and transmittances evaluated from existing computer codes. Furthermore, specific relationships are established between the distribution of absorptance and the electric field amplitude of the radiation. The significance of these relationships is discussed particularly in regard to mechanisms of laser damage.

Chemical vapor deposition of spectrally selective surfaces for high temperature photothermal conversion

Chemical vapor deposition was adapted to the fabrication of multilayer thin film systems of the spectral selectivity required for photothermal solar energy conversion. The systems operate on the principle of an absorber-reflector tandem, the absorption of the solar photons being accomplished by a layer of polycrystalline or amorphous silicon and the thermal emittance being reduced by a silver or molybdenum reflector. The surfaces were tested for several thousand hours at 500°C without degradation of their optical performance.

Electric fields in multilayers at oblique incidence

The recursion equation for electric field strength in a multilayer thin film system yields only the tangential component of the field. This paper discusses the relationship between the tangential component, the peak value, and the time average value of the total electric field for the two planes of polarization. This approach leads to easy understanding of the discontinuous field strength for p polarization and the relationship between the peak and time average field strengths. The results are applied to a polarizing beam splitter of the type used with high energy lasers.

Electron microscopy of multilayer thin films

A replica technique for obtaining electron micrographs of the cross-sectional structure of multilayer thin film systems is described in detail. The importance of such techniques is emphasised in the introductory section, and is attributed to the fact that they provide direct evidence of structural features whose existence has previously been inferred from measurements of the optical performance of the multilayer systems. Four micrographs are used to illustrate the usefulness of the technique, specifically in that they show structural features which could give rise to optical inhomogeneity and anisotropy in the layers as well as unevenness in the boundaries. It is also shown how measurement of the inter-boundary distances can provide information about the effectiveness of the optical thickness monitor used in the preparation of the multilayer system.