Lattice Dynamics of Sb2Se3from Inelastic Neutron and X‐Ray Scattering (original) (raw)
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Elastic, electronic, and optical properties of Sb2S3 and Sb2Se3 compounds: ab initio calculation
We have performed a first principles study of structural, mechanical, electronic, and optical properties of orthorhombic Sb2S3 and Sb2Se3 compounds using the density functional theory within the local density approximation. The lattice parameters, bulk modulus, and its pressure derivatives of these compounds have been obtained. The second-order elastic constants have been calculated, and the other related quantities such as the Young's modulus, shear modulus, Poisson's ratio, anisotropy factor, sound velocities, Debye temperature, and hardness have also been estimated in the present work. The linear photon-energy dependent dielectric functions and some optical properties such as the energy-loss function, the effective number of valance electrons and the effective optical dielectric constant are calculated. Our structural estimation and some other results are in agreement with the available experimental and theoretical data.
Solid State Sciences, 2012
We have performed a first principles study of structural, mechanical, electronic, and optical properties of orthorhombic Sb2S3 and Sb2Se3 compounds. The calculations have been carried out within the local density approximation using norm conserving pseudopotentials. The lattice parameters, bulk modulus, and its pressure derivatives of the these compounds have been obtained. The second-order elastic constants have been calculated, and the other related quantities such as the Young's modulus, shear modulus, Poisson's ratio, anisotropy factor, sound velocities and Debye temperature have also been estimated in the present work. The linear photon-energy dependent dielectric functions and some optical properties such as the energy-loss function, the effective number of valance electrons and the effective optical dielectric constant are calculated. Our structural estimation and some other results are in agreement with the available experimental and theoretical data. Responses to Technical Check Results
First-principles study of the lattice dynamics of Sb2S3
Physical Chemistry Chemical Physics, 2014
We present a lattice dynamics study of orthorhombic antimony sulphide (Sb2S3) obtained using density-functional calculations in conjunction with the supercell force-constant method. The effect of Born effective charges is taken into account using a mixed-space approach, resulting in the splitting of longitudinal and transverse optical (LO-TO) phonon branches near the zone center. Zone-center frequencies agree well with Raman scattering experiments. Due to the slow decay of the interatomic force constants (IFC), a minimal 2 × 4 × 2 supercell (P nma setting) with 320 atoms is crucial for an accurate determination of the dispersion relations. Smaller supercells result in artificial acoustic phonon softening and unphysical lifting of degeneracies along high symmetry directions. We propose a scheme to investigate the convergence of the IFC with respect to the supercell sizes. The phonon softening can be attributed to the periodic images that affect the accuracy of the force constants, and the truncation of long-ranged forces. The commensuration of the q-vectors with the supercell size is crucial to preserve degeneracies in Sb2S3 crystals.
A comparative study on the electronic and optical properties of Sb2Se3 thin film
Semiconductors, 2017
The thin film of Sb 2 Se 3 was deposited by thermal evaporation method and the film was annealed in N 2 flow in a three zone furnace at a temperature of 290 • C for 30 min. The structural properties were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy, respectively. It is seen that the as-deposited film is amorphous and the annealed film is polycrystalline in nature. The surface of Sb 2 Se 3 film is oxidized with a thickness of 1.15 nm investigated by X-ray photolecetron spectroscopy (XPS) measurement. Spectroscopic ellipsometry (SE) and UV-vis spectroscopy measurements were carried out to study the optical properties of Sb 2 Se 3 film. In addition, the first principles calculations were applied to study the electronic and optical properties of Sb 2 Se 3. From the theoretical calculation it is seen that Sb 2 Se 3 is intrinsically an indirect band gap semiconductor. Importantly, the experimental band gap is in good agreement with the theoretical band gap. Furthermore, the experimental values of n, k, ε 1 , and ε 2 are much closer to the theoretical results. However, the obtained large dielectric constants and refractive index values suggest that exciton binding energy in Sb 2 Se 3 should be relatively small and an antireflective coating is recommended to enhance the light absorption of Sb 2 Se 3 for thin film solar cells application.
XRD, SEM, AFM, HRTEM, EDAX and RBS studies of chemically deposited Sb2S3 and Sb2Se3 thin films
Applied Surface Science, 2002
Nanocrystalline thin films of Sb2S3 and Sb2Se3 are obtained at low temperature by simple chemical deposition method. The preparative parameters are optimized to get nanocrystalline films. The films are characterized for structural, surface morphological and compositional analyses by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), high-resolution transmission electron micrograph (HRTEM), energy-dispersive X-ray analyses (EDAX) and Rutherford back-scattering (RBS). XRD study confirms orthorhombic structure of Sb2S3 and Sb2Se3. Nanocrystallinity is evidenced from SEM, AFM and HRTEM studies with some random distribution of nanocrystallites. Stoichiometry of films are studied from EDAX and RBS analyses which showed some inclusion of oxygen in the films which is unavoidable for chemically deposited chalcogenides films.
Electronic structure and optical properties of Sb 2S 3 crystal
Physica B-condensed Matter, 2011
The electronic and optical properties of Sb2S3 are studied using the full potential linearized augmented plane wave (FP-LAPW) method as implemented in Wien2k. In this approach, the alternative form of the generalized gradient approximation (GGA) proposed by Engel and Vosko (EV-GGA) was used for the exchange correlation potential. The calculated band structure shows a direct band gap. The contribution of
Физика и техника полупроводников
The thin film of Sb2Se3 was deposited by thermal evaporation method and the film was annealed in N2 flow in a three zone furnace at a temperature of 290oC for 30 min. The structural properties were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy, respectively. It is seen that the as-deposited film is amorphous and the annealed film is polycrystalline in nature. The surface of Sb2Se3 film is oxidized with a thickness of 1.15 nm investigated by X-ray photolecetron spectroscopy (XPS) measurement. Spectroscopic ellipsometry (SE) and UV-vis spectroscopy measurements were carried out to study the optical properties of Sb2Se3 film. In addition, the first principles calculations were applied to study the electronic and optical properties of Sb2Se3. From the theoretical calculation it is seen that Sb2Se3 is intrinsically an indirect band gap semiconductor. Importantly, the experimental band gap is in ...