Recently, there is considerable interest in semiconductor diamond films prepared by vapor deposition. The fact originates from their unique properties and potential for the devices operating at high temperature and high power. What diamond films were feasible by vapor deposition, provide the driving force for developing diamond for advanced electronic devices. However, there exist many large barriers. Their presence tends to de-press futher progress in the investigation and industrialization.

The purpose of this paper is to point out the problems actually encountered in developing it and to describe its future direction on the basis of my present understanding.

Our recent report of epitaxial single crystal growth of C+ ion-beam-deposited diamond films on (111) single crystals of silicon is shown to be incorrect. We briefly describe the circumstances leading to this revision (and to our earlier finding) and discuss the possible structure of these films based on preliminary synchrotron X-ray data and on the Raman spectrum.

Diamond-like a-C:H films were obtained by reactive dc-magnetron sputtering from a glassy carbon target in an argon-hydrogen atmosphere. To our knowledge, this is the first time that glassy carbon is used as target material. The a-C:H films are transparent and hard. The a-C:H films can be used as protection and antireflection coatings on a-Si:H photoreceptors. The electrical, optical and structural properties of the a-C:H films are examined.

Ellipsometric measurements on plasma deposited “diamondlike” amorphous carbon (a-C:H) films were taken in the visible, (E = 1.75 to 3.5 eV). The films were deposited on Si and their properties were varied using high temperature (up to 750 °C) anneals. The real (n) and imaginary (k) parts of the complex index of refraction N were obtained simultaneously. Following the theory of Forouhi and Bloomer (Phys. Rev. B34, 7018 (1986)), a least squares fit was used to find the dispersion relations n(E) and k(E). Reasonably good fits were obtained, showing that the theory can be used for a-C:H films. Morever, the value of the energy gap Eg obtained in this way was compared to the Eg value using conventional Tauc plots and reasonably good agreement was obtained.

Diamondlike carbon (DLC) is amorphous, hard, semitransparent, and is under consideration for use as a coating material for infrared optics DLC is also designated as a-C:H to indicate its amorphous nature as well as to indicate the presence of large (20 to 55 percent) amounts of hydrogen in the film.

Diamond-like carbon (DLC) coatings have been deposited on several infrared transmitting substrates utilizing the ion beam deposition technique. Optimum deposition parameters have been established as a function of source gas composition, source pressure, ion-impact energy, substrate material and cleaning substrate procedures. Extensive characterization of the DLC films was also performed. Rutherford backscattering and proton recoil techniques were used to analyze carbon and hydrogen content and impurities. These films contain 70% atomic carbon and 30% atomic hydrogen. Transmission electron microscopy was used to analyze the crystallinity, void structure and surface microstructure, which were found to be amorphous and dense. Optical properties, such as refractive index and extinction coefficient, were measured using transmission/reflection spectroscopy, ellipsometry and laser calorimetry. Environmental testing was performed using various acids and solvents. The thermal stability and moisture penetration on these DLC films were extensively investigated. The effect of high ion energy radiation on DLC films was studied. Details of the preparation method and characterization of DLC films are presented.

The first generation of infrared optical waveguides operating in the mid I.R. region 0.3 to 4 μm is made from fluoride glasses based on zirconium tetrafluoride. A new family of vitreous materials based on indium fluoride appears to be also promising candidate. The state of art in the field including performances and limitations of these optical fibers will be described. A new class of heavy halide glasses based on tellurium chloride, bromide or iodide is presented in relation with their large optical transmission range covering the 8–12 μm region. First attempts in fiber preparation and planar waveguides deposition will be discussed and compared with the traditional chalcogenide glasses.

Single crystals of ZnSe have been grown by the physical vapor transport method in sealed quartz ampoules. The largest crystal grown measures 1 cm x 4 mm x 2 mm and required a total growing time of 11 days. Polished wafers cut from the crystals have been etched and examined by optical microscopy, x-ray diffraction, scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and scanning Auger microscopy (SAM). No impurities or unwanted phases were detected, but frequent twinning occurs. Zn-rich {111} faces were identified by SAM. Triangular etch pits are observed on Zn {lll} faces but not on Se faces. Etch pit densities are about 104 per cm2 on slow-cooled samples but are about 100 times greater when cooling is more rapid.

The growth and characterisation of a number of organic single crystals, e.g. benzil, 2–methyl–4– nitroaniline and 2–N,N–dimethylamino–5–nitroacetanilide, in silica capillary has become fairly well established over recent years. [1–6 ] However the growth of these same compounds in glass capillary with a much higher refractive index than silica has received little interest. Crystal cored fibres, ccf's, in which there is a close match of the refractive index of the cladding to that of the core allows the possibility of fabricating single mode waveguides with useful dimensions for crystal growth. There is a better overlap integral between phase matched fundamental and second harmonic modes in a low moded structure than in a structure with more allowable modes and thus a rise in the conversion efficiency can be expected if the correct dimensions of waveguide are chosen. If a ccf of high conversion efficiency, 10% at 0.1 mW average power, could be made then the promise of fabricating an organic optical nonlinear device, e.g. parametric amplifier, might be realised. In this paper we will describe how the growth method adopted for silica clad organic crystals has been adapted for their growth in a range of Schott glasses which are better matched in refractive index, RI, than silica to the organic material. The linear and nonlinear optical properties of these crystal cored fibres will be given in terms of; the orientation of the crystal axes with respect to the fibre direction; the sideways scattering characteristics from defects; the throughput of the fundamental beam; the polarisation states of both the fundamental and the second harmonic outputs; and the overall efficiency of second harmonic generation.

Non-oxide inorganic compounds such as sulfides, phosphides, and mixed-anion sulfidephosphides are of interest as possible infrared window materials. Our research on the solid state chemistry and structure-property relationships of these materials includes the directed synthesis of new compounds as well as the study of compounds that have been reported in the literature but which have been incompletely characterized for this application. The present work includes investigations of three ternary sulfide systems: ZnGa2S4, AIn2S4, (A = Ca,Sr,Ba), and CaY2S4. Samples were prepared in polycrystalline form and/or as crystals. New compounds were obtained in our studies of the CaIn2S4, SrIn2S4, and CaY2S4 systems. Compounds were characterized by X-ray diffraction, elemental analysis, FMR, and thermogravimetric analysis.

Ternary electrooptic oxides, with structures related to that of the perovskite, are used or being considered for potential utilization in optoelectronics technology [1,2]. Typical applications include electrooptic and acoustooptic modulators and switches, SAW and optical waveguide devices, non-linear optical components and pyroelectric and luminescent radiation and particle detectors. The use of these oxides as laser hosts has also often been contemplated.

The possible use of glasses as the nonlinear optical material in all-optical switching calls for glasses with nonlinear refractive indices much higher than those of vitreous silica. Relatively high values of the nonlinear index coefficient, n2, have been found in Na2O-TiO2-Nb2O5-SiO2 glasses, in which n2 is completely dominated by the Ti-O and Nb-O bonds. We have investigated the nonlinear optical properties of R2O-TiO2-Nb2O5-SiO2 glasses as a function of the monovalent ion R (Na, K, Rb, Cs, TI). The results show that the dependence of n2 on R is larger than predicted from the empirical relation between n2 and n. An especially large enhancement of n2 is seen for T1. This can be explained by the difference in electronic configuration between TI (unfilled shell) and the alkali ions (filled shell).

The optical properties of Cu+ doped Ag+-ß″-alumina are strongly affected by interactions between the d10 closed shell Cu+ and Ag+ ions. These effects can be distinguished from Cu+-Cu+ interactions previously observed in ß″-alumina, and produce a strong red emission upon ultraviolet excitation.

KTiOPO4 (KTP) is a nonlinear optical crystal presently used for second harmonic generation and electro-optic applications. The properties (ionic conductivity and damage susceptibility) of KTP crystals can vary depending on the specific technique and conditions used for growth. Consistent defect mechanisms have been determined to explain the observed AC conductivity and damage results of KTP grown by the flux and high and low temperature hydrothermal techniques. The presence of nonstoichiometry on the K and O sublattices in KTP, increasing in magnitude with temperature, is proposed. Using these defect mechanisms, the predominant defects compensating for the formation of vacant potassium sites (VK's) in flux and hydrothermal materials are vacant oxygen sites (VO's) and OH−'s, respectively. The presence of a more varied distribution of OH− sites at room temperature in high temperature hydrothermal material with higher AC conductivity indicates the importance of specific OH− sites in the lattice that may enhance the mobility of ionic carriers. The correlation of higher AC conductivity to increased average current and damage in electric field treated KTP is explained on the basis of the proposed compensating defects (VO 's and OH− 's) which set the [VK] and [Ti3+]. The similarity of the linear optical properties of KTP grown by the various techniques is confirmed by the insensitivity of the absorption edge to the nonstoichiometry or defects present.

The microstructure and optical properties of vacuum evaporated coatings are a sensitive function of the deposition conditions. In recent years, ion bombardment has been used increasingly for the production of denser, more stable coatings of oxides and other materials. In addition to modifying the microstructure, ion bombardment is emerging as a valuable tool for altering the composition (and hence the optical properties) of thin films. A discussion of the effects of ion beam processing and the methods used to analyze the changes in these films is presented.

The refractive indices and optical absorptions of Cu implanted glasses have been measured. Silica and two silicate glasses have been implanted with Cu+ to nominal doses ranging from 3×1015 cm−2 to 6×1016 cm−2 at an energy of 160KeV and currents of ∼4μAcm−2. Substrate temperatures, during implantation, ranged from ∼100K to 700K. Both refractive index and optical absorption of the silica are functions of dose and substrate temperature. Neither of these properties are significantly altered in the silicate glasses for any dose or substrate temperature. The observed increases in the index of the implanted silica are attributed to an optical band due to Cu0 colloids.

The microstructures associated with pulsed-laser heating of multilayer thin films used for phase-change optical data storage are studied in three related films. Two employ the multilayer structure SiOx/TeGeSn/SiOx where the chalcogenide layer is either amorphous or crystalline. The third uses the same trilayer structure with a crystalline chalcogenide layer but with an additional layer of aluminum. Pulsed-laser melting of micron-sized spots leads to solidification in the non-aluminized specimens with a morphology dependent on the preexisting structure of the chalcogenide layer and to amorphization in the aluminized film. Heat-flow modelling shows that the maximum temperature reached is lower and the cooling rate through the glass-forming temperature range higher in the aluminized structure. Discussion centers on the thermal and optical properties of the different films and the impact of the pre-existing chalcogenide structure on the subsequent phase transformations.

The effect of 647nm Kr-ion laser and 514.5 nm Ar-ion irradiation on 1 and 7 μm diameter regions, respectively, of (In43Sb57)87 Ge13 thin alloy films was determined. Laser irradiation times of 50ns - 20μs produce different reflectivity states. An amorphous state of increased reflectivity with respect to the as-deposited amorphous state was produced only with the smaller beam after short pulse (∼100ns to ∼500ns) laser irradiation. Slightly longer pulses caused formation of surface corrugations. The corrugation morphology occurred in the nanosecond regime both in air and vacuum. Further laser annealing caused crystallization and decreased reflectivity. The crystallization microstructures were random cellular for the irradiation in air. Irradiation in vacuum produced three, distinct concentric structures.

Polycrystalline magnesium aluminate spinel (MgAl2O4) and Al23O27 N5 (ALON) were irradiated with 4 MeV Ar+ ions to doses from 0.5 to 6 displacements per atom (dpa) at a temperature of 1070K and subsequently examined using transmission electron microscopy. Faulted dislocation loops were found in both materials, although their habit planes ({110} and {111} respectively) and Burgers vectors (a/4 <110> and a/6 <111>) differ. Cavities were found in spinel but not in ALON. Both materials exhibited a similar, low, degree of radiation damage and we conclude that polycrystalline ALON is a good potential reactor window material.

The modification of the chemical structure of fluorozirconate glasses (ZBLAN) with Ar ion and atom beams of low energy (2–10 key) has been studied in comparison with the damage produced in the starting polycrystalline ZrF4 and BaF2. A variety of reduced chemical states of Zr is produced in ZrF4 as well as in ZBLAN glasses, including metallic Zr0 state. A strong enhancement of the amount of the metallic Zr formed under irradiation is observed in ZBLAN, while it is present only as trace in the irradiated pure ZrF4 samples. The reported effect is tentatively attributed to the presence of Ba ions in the glass network which could prompt the self-trapping of radiation-induced defects at the Zr sites, involving their progressive reduction