Search results for "conductors"
showing 10 items of 254 documents
Thermal sensor based on a polymer nanofilm
2016
In this work, we have developed a thermal sensor based on poly(3,4 ethylenedioxythiophene) (PEDOT) nanofilms as thermoelectric material. The PEDOT nanofilms have been synthesized by the electrochemical polymerization method. The thicknesses of the films were around 120 nm. The doping level of PEDOT was controlled by chemical reduction using hydrazine. The achieved Seebeck coeficient is 40 uV/K. A PEDOT nanofilm was integrated into an electronic circuit that amplifies the voltage originated from the Seebeck effect. The temperature increment produced by a fingerprint touching the film is enough to switch on a light emitting diode. Peer Reviewed
Theoretical study of Zn and Cd interstitials and substitutional interstitials in CuInSe2 via hybrid functional calculations
2013
We have investigated the formation of Zn and Cd interstitials in the CuInSe2 solar cell material via density-functional-theory (DFT) calculations by employing the HSE06 hybrid functional. The computed formation energies for Zn interstitials were in the range of 2.09-2.68 e V, and in the range of 2.04-2.25 eV for substitutional interstitials. In constrast, the formation energies of Cd interstitials and substitutional interstitials were between 1.85-2.75 eV and 2.41-2.64 eV, respectively. Thus, these results indicate, that Cd interstitials are more likely to be formed than Zn interstitials, and that in case of Zn inclusion into CuInSe2 Zn atoms will prefer to adopt substitutional interstitial…
Time propagation of the Kadanoff–Baym equations for inhomogeneous systems
2009
We have developed a time propagation scheme for the Kadanoff-Baym equations for general inhomogeneous systems. These equations describe the time evolution of the nonequilibrium Green function for interacting many-body systems in the presence of time-dependent external fields. The external fields are treated nonperturbatively whereas the many-body interactions are incorporated perturbatively using Phi-derivable self-energy approximations that guarantee the satisfaction of the macroscopic conservation laws of the system. These approximations are discussed in detail for the time-dependent Hartree-Fock, the second Born and the GW approximation.
Comparison of single-spot technique and RGB imaging for erythema index estimation
2016
A commercially available point measurement device, the Mexameter(®), and an experimental RGB imaging prototype device were used for erythema index estimation of 50 rosacea patients by analysing the level of skin redness on the forehead, both cheeks and both sides of a nose. Results are compared with Clinician's Erythema Assessment (CEA) values given by two dermatologists. The Mexameter uses 568 nm and 660 nm LEDs and a photodetector for estimation of erythema index, while the used prototype device acquired RGB images at 460 nm, 530 nm and 665 nm LED illumination. Several erythema index estimation algorithms were compared to determine which one gives the best contrast between increased eryth…
<title>Holographic recording in amorphous semiconductor films</title>
1997
The present state of the real time holographic recording in amorphous semiconductor films is reviewed including mechanisms, parameters, properties and applications. Effects of the coherent, incoherent and relaxational self- enhancement as well as the influence of the film structure relaxation are considered. Quasi-permanent sub-band-gap light holographic recording is reported for the first time. 157
Structural, vibrational and electrical study of compressed BiTeBr
2016
Compresed BiTeBr has been studied from a joint experimental and theoretical perspective. Room-temperature x-ray diffraction, Raman scattering, and transport measurements at high pressures have been performed in this layered semiconductor and interpreted with the help of ab initio calculations. A reversible first-order phase transition has been observed above 6–7 GPa, but changes in structural, vibrational, and electrical properties have also been noted near 2 GPa. Structural and vibrational changes are likely due to the hardening of interlayer forces rather than to a second-order isostructural phase transition while electrical changes are mainly attributed to changes in the electron mobilit…
Facile fabrication of flower like self-assembled mesoporous hierarchical microarchitectures of In(OH)3 and In2O3: In(OH)3 micro flowers with electron…
2016
Abstract A template and capping-reagent free facile fabrication method for mesoporous hierarchical microarchitectures of flower-like In(OH) 3 particles under benign hydrothermal conditions is reported. Calcination of In(OH) 3 to In 2 O 3 with the retention of morphology is also described. Both In(OH) 3 and In 2 O 3 microstructures were analyzed with SEM, EDX, TEM and powder X-ray diffraction. The crystal sizes for In(OH) 3 and In 2 O 3 were calculated using the Scherrer equation. In In(OH) 3 the thin flakes at the periphery of micro flowers were electron beam sensitive. The mechanism of self-assembly process was analyzed as well.
Raman scattering and infrared reflectivity in [(InP)5(In0.49Ga0.51As)8]30 superlattices
2000
6 páginas, 6 figuras, 1 tabla.
Phonon-induced optical superlattice
2005
We demonstrate the formation of a dynamic optical superlattice through the modulation of a semiconductor microcavity by stimulated acoustic phonons. The high coherent phonon population produces a folded optical dispersion relation with well-defined energy gaps and renormalized energy levels, which are accessed using reflection and diffraction experiments.
Structural and elastic properties of defect chalcopyrite HgGa2S4 under high pressure
2014
In this work, we focus on the study of the structural and elastic properties of mercury digallium sulfide (HgGa2S4) at high pressures. This compound belongs to the family of AB(2)X(4) ordered-vacancy compounds and exhibits a tetragonal defect chalcopyrite structure. X-ray diffraction measurements at room temperature have been performed under compression up to 15.1 GPa in a diamond anvil cell. Our measurements have been complemented and compared with ab initio total energy calculations. The axial compressibility and the equation of state of the low-pressure phase of HgGa2S4 have been experimentally and theoretically determined and compared to other related ordered-vacancy compounds. The pres…