Experimental data on the wavelength dependence of the refractive index in the wavelength range 0.3–1.0 μm is presented for thin films of BaTiO3 and SrTiO3. The films of thickness 1–4 μm were prepared by sputter deposition at substrate temperatures of 300 to 600 K, resulting in amorphous films at the lower temperatures and ’’microcrystalline’’ films at the higher. Both thin-film phases have a lower index at a given wavelength than the corresponding crystalline value (e.g., at λ=5000 Å, n=2.00, 2.07, and 2.51 for amorphous, microcrystalline, and crystalline BaTiO3, respectively). The dispersion of the refractive index in the thin films follows a single-oscillator model with a higher oscillator energy and smaller oscillator strength than in the crystalline phase.

The behavior of amorphous Si in contact with Ag films and Ge in contact with Al films has been studied at temperatures well below those at which any liquid phase is present. MeV 4He+ ion backscattering techniques, transmission electron diffraction, scanning electron microscopy, and electron microprobe analysis have been used. We find that of the many possible reactions which carry the amorphous Si or Ge into their crystalline forms the reaction predominating under our experimental conditions consists of dissolution, diffusion, and crystal growth. During isothermal heat treatment, the semiconductor film is dissolved into the metal film where it diffuses and precipitates as crystalline Si or Ge. These processes are solid-solid reactions, since this behavior is observed over temperatures of 300°C to as low as 100°C for GelAI, compared to the 424°C eutectic in this system. In Sil Ag, this behavior was observed from 700 to 400°C, compared with the 840°C eutectic.

We demonstrate for the first time that Te87Ge8Sn5 films, which are amorphous as deposited, can be optically switched between the crystalline and amorphous states more than 106 times. The measured reflectivity changed from 40% to 60% and the transmission changed from 3% to 1.5%, respectively, between the amorphous and crystalline states. The crystallization temperature of the cycled spots is ≊75 °C and these spots are observable after >20 weeks. It is found that the crystallization temperature of cycled spots is typically about 20 °C lower than that of the unwritten film. Increasing the Ge concentration leads to increased crystallization temperature and increased minimum crystallization time without affecting reversibility.

The ac thin-film electroluminescence devices employing ZnS : Mn as the active medium exhibit a ’’memory effect’’ which in turn is related to filamentary luminescence. Under certain film preparation and device excitation conditions, it is found that the filaments exhibit a large scale cooperative motion. Spontaneously moving spirals and stripes have been observed under steady-state conditions. This paper describes the phenomena, and a thermal model for the observations is proposed.

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