H. Albers

Luminescent thin films by the chemical aerosol deposition technology (CADT)

Zinc sulphide thin films have been deposited with CART using zinc chlorideand zinc acetylacetonate as Zn compounds and thiourea and 1,1,3,3-tetramethylthiourea as S compounds soluted in methanol, ethanol, isopropanol and cellosolve. After optimalization of the deposition process homogeneous layers with a c-axis oriented hexagonal columnar structure with a high density (up to 96%) were obtained. Luminescence was observed with films grown above 500°C. The influence of the hot plate temperature, flow of carrier gas, nozzle geometry, distance nozzle substrate, and volatility of the solvent and reactants on the growth rate, homogenity and density of the film has been shown. Some rules for the selection of the starting compound are given. TG analyses of the reactant compounds was used to compare their volatility and stability.

Noncritically phase-matched second harmonic generation of blue light in Si[O]N-calix[4]arene slab type waveguides

Phase-matching (TM(0)(omega) --> TM(1)(2 omega)) devices for generation of blue light using Si[0]N and optically nonlinear calix[4]arene layers are designed, fabricated and tested. The devices show second harmonic peak power of 17 mW at 472.9 nm and 4.5 W at 481.6 nm after 10 mm propagation length of a 1 mm broad beam using fundamental peak power of 200 W and 500 W, respectively. The strong requirements of noncritical phase match are fulfilled, in both design and realization, by the excellent process controllability of the passive Si[O]N waveguides and the insensitivity of the devices towards technologically critical parameters, mainly the calix [4] arene layer thickness.

Granular YBaCuO films prepared by metalorganic chemical aerosol deposition technology

Fine-grain thin superconducting films can be prepared by metalorganic Chemical Aerosol Deposition Technology (CADT). In this paper, we present the preparation and properties of YBa2Cu3O7-x films on the different substrates, Si and SrTiO3 (100). It is shown that the zero-resistance temperature (Tc,0) of the films on SrTiO3 substrates is about 90 K, and the critical current density (Jc) at 77 K is above 104 A/cm2. In addition, these films exhibit significant grain-boundary weak link behaviour, which is very promising for applications in electronic devices.

Phase matched second harmonic generation in silicon [Oxy]nitride-calix[4]arene waveguides

width of less than or equal to 8 pm operate in a single mode, but the waveguides with a core width of more than 8 pm operate in multiple modes. Figure 3 shows the dependence of optical loss on core width. The optical loss is constant for TE polarized incident light, even though the core width increases. On the other hand, the optical loss decreases with increasing core width for TM polarized incident light. The lowest optical loss at 1.3 pm among the waveguides which operate in a single mode was when the core width was 8 pm; the values were 0.4 dB/cm for TE and 0.7 dB/cm for TM polarized incident lights. In conclusion, we showed that embedded channel waveguides can be fabricated by direct electron beam writing. By controlling conditions appropriately, we can get single mode transmission and low optical loss. *NTT Opto-electronics Laboratories, 9-11, Midori-cho 3-chome Musashino-shi, Tokyo 180 Japan