22 research outputs found
Solvothermal Synthesis of Ternary Sulfides of Sb2 − xBixS3(x = 0.4, 1) with 3D Flower-Like Architectures
Flower-like nanostructures of Sb2 − xBixS3(x = 0.4, 1.0) were successfully prepared using both antimony diethyldithiocarbamate [Sb(DDTC)3] and bismuth diethyldithiocarbamate [Bi(DDTC)3] as precursors under solvothermal conditions at 180 °C. The prepared Sb2 − xBixS3 with flower-like 3D architectures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), high-resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED). The flower-like architectures, with an average diameter of ~4 μm, were composed of single-crystalline nanorods with orthorhombic structures. The optical absorption properties of the Sb2 − xBixS3 nanostructures were investigated by UV–Visible spectroscopy, and the results indicate that the Sb2 − xBixS3 compounds are semiconducting with direct band gaps of 1.32 and 1.30 eV for x = 0.4 and 1.0, respectively. On the basis of the experimental results, a possible growth mechanism for the flower-like Sb2 − xBixS3 nanostructures is suggested
Prevalence of drug-resistant pulmonary tuberculosis in India: systematic review and meta-analysis
Mathematical model simulating the growth of compound semiconductor thin films via chemical bath deposition
Chemical bath deposition is a thin film technique in which compound semiconductor thin films of typically 0.02-1 mu m thickness are deposited on the substrates immersed in dilute baths containing metal ions and a source of sulfide or selenide ions. Many I-VI, II-VI, IV-VI, and V-VI semiconductors are included in the list of materials deposited by this technique. However, a mathematical model describing the growth mechanism of these films in the context of batch production of large area thin films still remains to be established. The deposition process consists of a nucleation phase, growth phase, and a terminal phase, each of which depends on the concentration of the ions in the deposition bath, the temperature of the deposition, dissociation constants of the metal complex ions, etc. In this paper we propose a mathematical model which can qualitatively account for most of the features of the experimental growth curves of the chemically deposited semiconductor thin films. (C) 1999 Elsevier Science B.V. All rights reserved