Optical and photoelectric properties of lamellar nanocomposites obtained by Cd intercalation of GaTe

Date du colloque : 05/2013 International audienc

Composition and structure of lamellar composites obtained by intercalation of III-VI layered semiconductor materials

Date du colloque : 05/2013International audienc

Optical and photosensitive properties of lamellar nanocomposites obtained by Cd intercalation of GaTe

By Cd-vapor heat treatment, at temperatures from 623 to 833 K, of GaTe single crystals, GaTe-CdTe composite is formed. CdTe amount is increasing together with heat treatment temperature. Absorption, photoconductivity and photoluminescence spectra of the composite contain particularities characteristic to GaTe and CdTe components. The absorption and photoconductivity edges display two thresholds at 1.66 eV (GaTe) and 1.50 eV (CdTe). Short lifetime recombination states form at the surface of composite samples, leading to narrowing of the photoconductivity bands in the high energy region, up to 1.8 eV. Widening of the absorption and photoconductivity bands in the low energy region is determined by absorption processes taking place in both GaTe and CdTe components

A comparative study of ZnO, In2O3 SnO2 CdS CdTe Cu Ni heterojunctions

The influence of the manufacturing technology on the structural properties of CdTe and CdS layers, components of the CdS CdTe solar cells, has been investigated. CdTe based solar cells have been prepared using glass substrates coated with different transparent conductive oxides TCOs SnO2, In2O3 SnO2 ITO , ZnO Al, ZnO Al i ZnO . The analysis of the technology combined with various investigation methods allowed to determine optimum deposition parameters for CdS and CdTe for each type of TCO used. X ray diffraction XRD and grazing incidence XRD analysis have been carried out for TCO, CdS, and CdTe layers at different deposition stages before and after annealing in the presence of CdCl2 in air. The reflection spectra in the 100 600 cm amp; 8722;1 spectral region have been thoroughly studied by using Fourier transform infrared spectroscopy. It was found that i the best quality possess CdS and CdTe thin films sequentially deposited on ZnO Al substrates and that ii the pre treatment defects can be effectively cured and most of the secondary phases can be removed by annealing, while the basic structure of the investigated thin films does not essentially chang

Doped GaSe crystals for laser frequency conversion

In this review, we introduce the current state of the art of the growth technology of pure, lightly doped, and heavily doped (solid solution) nonlinear gallium selenide (GaSe) crystals that are able to generate broadband emission from the near infrared (IR) (0.8 mm) through the mid- and far-IR (terahertz (THz)) ranges and further into the millimeter wave (5.64 mm) range. For the first time, we show that appropriate doping is an efficient method controlling a range of the physical properties of GaSe crystals that are responsible for frequency conversion efficiency and exploitation parameters. After appropriate doping, uniform crystals grown by a modified technology with heat field rotation possess up to 3 times lower absorption coefficient in the main transparency window and THz range. Moreover, doping provides the following benefits: raises by up to 5 times the optical damage threshold; almost eliminates two-photon absorption; allows for dispersion control in the THz range independent of the mid-IR dispersion; and enables crystal processing in arbitrary directions due to the strengthened lattice. Finally, doped GaSe demonstrated better usefulness for processing compared with GaSe grown by the conventional technology and up to 15 times higher frequency conversion efficiency