New generation adsorbents for water treatment.

http://nathan.instras.com/documentDB/paper-44.pdf

Surface photovoltage phenomena: theory, experiment, and applications

Tin doped indium oxide (ITO) films are highly transparent in the visible region, exhibiting high reflectance in the infrared region, and having nearly metallic conductivity. Owing to this unusual combination of electrical and optical properties, this material is widely applied in optoelectronic devices. The association of these properties in a single material explains the vast domain of its applicability and the diverse production methods which have emerged. Although the different properties of tin doped indium oxide in the film form are interdependent, this article mainly focuses on the electrical aspects. Detailed description of the conduction mechanism and the main parameters that control the conductivity is presented. On account of the large varieties and differences in the fabrication techniques, the electrical properties of ITO films are discussed and compared within each technique.

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Tin doped indium oxide thin films: Electrical properties

▪ Abstract The synthesis of nanocrystalline diamond films from carbon-containing noble gas plasmas is described. The nanocrystallinity is the result of new growth and nucleation mechanisms, which involve the insertion of C2, carbon dimer, into carbon-carbon and carbon-hydrogen bonds, resulting in hetereogeneous nucleation rates on the order 1010 cm−2 s−1. Extensive characterization studies led to the conclusion that phase-pure diamond is produced with a microstructure consisting of randomly oriented 3–15-nm crystallites. By adjusting the noble gas/hydrogen ratio in the gas mixture, a continuous transition from micro- to nanocrystallinity is achieved. Up to 10% of the total carbon in the nanocrystalline films is located at 2 to 4 atom-wide grain boundaries. Because the grain boundary carbon is π-bonded, the mechanical, electrical, and optical properties of nanocrystalline diamond are profoundly altered. Nanocrystalline diamond films are unique new materials with applications in fields as diverse as tribolo...

Nanocrystalline diamond films1

We analyze theoretically the optical properties of ideal semiconductor crystallites so small that they show quantum confinement in all three dimensions [quantum dots (QD's)]. In the limit of a QD much smaller than the bulk exciton size, the linear spectrum will be a series of lines, and we consider the phonon broadening of these lines. The lowest interband transition will saturate like a two-level system, without exchange and Coulomb screening. Depending on the broadening, the absorption and the changes in absorption and refractive index resulting from saturation can become very large, and the local-field effects can become so strong as to give optical bistability without external feedback. The small QD limit is more readily achieved with narrow-band-gap semiconductors.

Theory of the linear and nonlinear optical properties of semiconductor microcrystallites

Preparation and characterization of polycrystalline ZnSxSe1−x films prepared by a two-zone hot wall technique

Optical properties of nanocrystalline gallium nitride films

Nanostructured CdS films are deposited by the high pressure magnetron sputtering technique onto glass and NaCl substrates at various substrate temperatures and at a fixed gas pressure. Electrical conductivity of these nano CdS films in dark and when illuminated is measured. It is observed that the conduction mechanism is dominated by the combined effects of thermionic emission, tunneling, and variable range hopping.

Dark and photoconductivity of nanocrystalline CdS films

Hopping conduction in nanocrystalline ZnSe films deposited by high pressure d.c. magnetron sputtering

A comprehensive model has been developed for the determination of the strain, stress and microhardness of polycrystalline thin films from the below-band-gap optical absorption data which reflect the defect states at the grain boundary regions. The model has been applied to describe the absorption data of AlN and diamond films and consequent interpretation of the mechanical properties of the same is presented.

A.K. Pal

Papers

Preparation and characterization of polycrystalline ZnSxSe1−x films prepared by a two-zone hot wall technique

Optical properties of nanocrystalline gallium nitride films

Dark and photoconductivity of nanocrystalline CdS films

Hopping conduction in nanocrystalline ZnSe films deposited by high pressure d.c. magnetron sputtering

Stress and microhardness in polycrystalline thin films from below-band-gap absorption studies