A preliminary device was investigated as a first step in making an on-chip electrical readout based on the semiconductor CdS for a novel 3-D optical data storage method. The optical data is stored in glass as subsurface nanometer size defects called voxels. These voxels display secondary harmonic generation (SHG) to 800 nm input light. The device begins with an indium tin oxide film on a glass substrate coated with a film of Al2O3. In this preliminary device the Al2O3 was patterned via optical lithography with a periodic array of 10 micron holes that were filled with electrodeposited CdS. X-ray diffraction, and energy dispersive X-ray analysis were used to characterize the CdS. The device operation depends on the ability of the CdS with a bandgap of 2.4 eV to detect the 3.1 eV SHG light from the voxels while remaining unresponsive to 1.6 eV input light. The electrodeposited CdS was found to absorb 400 nm light at least a factor of 10 times greater than 800 nm light. Light to dark photocurrent ratios of 15 to 63 were observed from the CdS pillars using a 150 W xenon broadband light source. A light to dark ratio of about one was found when a long pass optical filter allowed only wavelengths above 750 nm. Thus the 10 micron CdS pillars have detected 400 nm light while rejecting the 800 nm input light.

Sol-gel processing was used to dope photochromic materials into metal alkoxide-polymer and pure polymer materials. The films on silicon and quartz substrates were examined, with and without UV irradiation, by UV/VIS spectroscopy, ellipsometry and FTIR.

The UV/VIS spectroscopy showed that the doped matrices were photochromic in the visible and near infrared.

The ellipsometric data were obtained with a variable angle of incidence spectroscopie ellipsometer (VASE). The Cauchy and a combined Cauchy-Lorentz model were used to fit the unirradiated and irradiated films, respectively. The optical constants of the films showed significant changes upon irradiation. This means that the absorption coefficient and hence the emissivity of the films is being modulated with UV irradiation. The VASE-fitted thicknesses of the films were in the range of 1 to 6 microns.

In the FTIR spectra, the spiropyran doped samples have shown IR transmission changes in the two spectral regions (6–7 μm and 7.5–8.5 μm) where changes are expected due to band opening. The transmission ratio for UV irradiated to unirradiated samples decreased by as much as about 24% at aparticular IR wavelength.

We have studied the electrical properties of boron doped composite films that consist of diamond and amorphous carbon. These films were deposited by hot filament chemical vapor deposition at a relatively high carbon/hydrogen ratio. The mixture of trimethyl borate vapor, and methane served as a source gas. The composite films had much smoother surfaces than polycrystalline diamond films.

The surface morphology and average roughness were determined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Raman spectroscopy and x-ray diffraction were used to analyze the structure of the films.

A composite film grown with 4% methane in hydrogen had a higher resistivity than a well faceted diamond film grown at 0.5% methane. In contrast to hydrogenated amorphous carbon films which have a lower resistivity after thermal annealing, the resistivities of composite films increased by a factor of two to ten after 3 hours annealing at 600°C.

The thermal stresses induced by temperature variations that exist during steady-state Czochralski growth produce plastic deformations in the crystal by dislocation motion and generation. The temperature variations in the crystal are calculated numerically by the finite element method (FEM). Employing the Haasen-Sumino viscoplastic response function for silicon and the calculated temperature profile, the thermal stresses, the dislocation densities, and the residual stresses in the crystal are also calculated. Only low dislocation densities are of interest and hence the associated viscoplastic deformations are found to be small. The assumption is made that there is a very low dislocation density along the solid-melt interface. The Haasen-Sumino material model is modified to include a back-stress to account for the locking effects due to the impurity concentration in the crystal. This analysis provides guidance for growing large diameter crystal of materials with known constitutive relations which have a low dislocation density and low thermal stresses.