Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cadmium selenide (CdSe) thin films were chemically deposited at room temperature, from aqueous ammoniacal solution using Cd(CH(3)COO)(2) as Cd2+ and Na(2)SeSO(3) as Se2- ion sources. The as-deposited films were uniform, well adherent to the glass substrate, specularly reflective, and red-orange in color. The as-deposited CdSe layers grew with nanocrystalline sphalerite cubic structure along with the amorphous phase present in it, with optical band gap E(g) = 2.3 eV. The films were annealed in air atmosphere for 4 h at different temperatures and characterized for compositional, structural, morphological, and optical properties. XRD and SEM studies clearly revealed the systematic phase transformation of CdSe films from metastable nanocrystalline cubic (zinc blende type) to a mixture of cubic and hexagonal (wurtzite type), and finally into stable hexagonal through different intermediate phases with an improvement in the crystal quality. The films showed a red shift in their optical spectra after annealing.
 ...
PMID:Systematic study on structural phase behavior of CdSe thin films. 1685 24

In the present paper, the properties of Cu(In(1-x) Ga(x)) Se2 (CIGS) thin film absorber materials for the solar cells obtained by selenization of the precursors with In-rich or CuGa-rich surface layers were studied by XRD, SEM and Raman spectra. The photovoltaic devices based on the absorbers were measured and analyzed by illuminated J-V curve subsequently. The performance of the device constructed by the absorbers obtained by selenization of the precursors with CuGa-rich surface layer was improved greatly compared to that with In-rich surface layer. Through Raman spectra measurement, it was found that the Raman peak of the A1 mode was shifted for the CuGa-rich one, which is verified that the band gap of the surface layers was elevated. Moreover the value of increased Ga contents within the surface region of films were calculated by the relation between the Raman shifts and the Ga contents. As a result, the devices based on the thin films with the elevated surface energy band by selenizing the precursors with the CuGa-rich surface layer improved further the V(oc) and FF by about 74 mV and 8% respectively compared to that of corresponding to the one with In-rich surface layers, so that the conversion efficiency of the photovoltaic devices based on these thin films with CuGa-rich surface layer was improved by up to 9.4%. Meanwhile Raman scattering spectroscopy has proven to be a very powerful and useful technique for the surface analysis of such thin film solar cell semiconducuor materials.
 ...
PMID:[Study on the modified surface layers of the CIGS thin films by Raman spectra]. 1760 82

A novel aqueous phase synthetic route for CuInSe2 nanoparticles is presented. In our synthesis, the Se precursor used was Na2SeSO3 and CuI, while InCl3 were used as precursors for copper and indium, respectively. The reaction was performed in water under basic condition in the presence of thioglycolic acid (TGA). TGA has a crucial effect on the formation of CIS nanocrystals in aqueous media. With less amount of TGA compared to the optimum amount, only amorphous CIS was formed while larger amount caused the formation of Cu2-xSe crystals because TGA had a lower reactivity of In3+ to Se2- ion. The ratio of reagents used optimized the structure, while the composition and properties of the nanomaterials obtained were studied applying various techniques such as XRD, SEM, TEM, TG/DSC, and XPS.
 ...
PMID:A novel aqueous phase synthetic route for CuInSe2 nanocrystals. 2296 76