Photodetector Based on Titanium Oxide Nanoparticles Produced via Pulsed Laser AblationRead the full article
Advances in Condensed Matter Physics publishes research on the experimental and theoretical study of the physics of materials in solid, liquid, amorphous, and exotic states.
Chief Editor, Professor Ulloa, is based at Ohio University and is a condensed matter theorist. His research is focussed on the electronic properties of nanostructures including quantum dots and nanowires, as well as proximity effects in 2D crystals.
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Structural and Morphological Properties of Single and Mixed Halide Pb-Based Perovskites
Single and mixed-halide perovskite solar cells have attracted much research attention in recent years due to the conditions of low-cost thin film solar cell technology. For this current research, perovskite materials CH3NH3PbCl3, CH3NH3PbI2Cl, CH3NH3PbICl2, and CH3NH3PbI3 have been synthesized and deposited on clean glass substrates by spin coating process. The structural and morphological properties of the prepared thin films have been studied by X-ray diffraction and Scanning electron microscopy. All the perovskite showed fine crystallinity, possessing a tetragonal phase. The average crystallite sizes of the prepared samples are obtained to be 20.77 nm, 30.18 nm, 31.11 nm, and 42.23 nm, respectively. The lattice strain decreased with increasing crystallite size. A drastic change was observed in the morphological properties of the perovskites. The perovskite grains change from microrods to microcube by substituting iodine with chlorine ions.
Enhanced Light Emission from Type-II Red InGaN/GaNSb/GaN Quantum-Well Structures
Electronic and optical properties of type-II InGaN/GaNSb/GaN quantum-well (QW) structures are investigated by using the multiband effective mass theory for potential applications in red light-emitting diodes. The heavy-hole effective mass around the topmost valence band is not affected much by the insertion of the GaNSb layer, and the optical matrix elements are greatly increased by the inclusion of the GaNSb layer in the InGaN/GaN QW structure. As a result, the type-II InGaN/GaNSb/GaN QW structure shows a much larger emission peak than the conventional type-I QW structure owing to the decrease in spatial separation between electron and hole wavefunctions, in addition to the reduction of the effective well width. It is also observed that the In content in InGaN well can be significantly reduced for the type-II QW structure with a large Sb content, compared to that for the type-I QW structure.
Thermal Spin Transport Properties in Diarylethene-Based Molecule Devices
Spin caloritronic devices, as multifunctional devices, combining spintronics, and caloritronics, are essential for the sustainable development of humans. Here, a novel spin caloritronic device is presented using a diarylethene molecule photoswitch sandwiched among two semi-infinite zigzag graphene nanoribbons containing asymmetrical edge hydrogenation electrodes. We demonstrate that the temperature gradient between the right and the left electrodes can generate spin-up (SU) and spin-down (SD) currents moving in opposite orientations. Moreover, the mentioned currents possess approximately the same magnitudes, indicating a nearly nondissipative spin Seebeck effect. We also find that these currents are significantly dissimilar for the two photochromic isomers at different temperature gradients, demonstrating the excellent system’s switching nature. The obtained results reveal that the light can control the thermal spin transport properties.
Dielectric and Impedance Spectroscopic Investigation of (3-Nitrophenol) -2,4,6-Triamino-1,3,5- Triazine: An Organic Crystalline Material
This article presents the investigation of dielectric and impedance spectroscopic properties of an organic product of 3-nitrophenol -2,4,6-tri amino-1,3,5- triazine (3NPTAT) single crystal, synthesized from melamine and m-nitrophenol. Comprehensive dielectric studies and charge transportation properties of the grown 3NPTAT crystal are given. The dielectric characteristics of the specimen were carried out in the frequency range of 50 Hz and 5 MHz at different temperatures, namely, 313 K, 333 K, 353 K, and 373 K. From the spectra, it was observed that the slowdown occurs at low temperatures, and the hopping mechanism takes place based on localized charge carriers. The impedance spectroscopic results indicate that there is a single relaxation process that occurs at high frequencies. The variation detected in the material properties of 3NPTAT corresponding to the temperature and frequency has been discussed in detail.
Characterization of Blue Tourmaline from Madagascar for Exploring Its Color Origin
In the research, spectroscopic studies of tourmaline for color origin were performed by X-ray diffraction, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, and X-ray photoelectron spectroscopy. The research work emphasized the analysis of transition metal atoms, including their valence state and coordination number, in order to better understand the effect of transition metal cations on the color origin. The results showed that the blue color of the crystal is caused by the strong absorption at 725 nm in the red spectrum, which generates a symmetrical and wide absorption band. The absorption band at 725 nm is caused by charge transfer between Fe2+ at the Y site and Fe3+ at the Z site. Other ions in the crystal did not generate absorption lines in the visible spectral range. Besides position, its valence state and coordination number were clarified to reveal color variation and the origin of tourmaline. Most importantly, this spectroscopic analysis method makes the coloration mechanism of charge transfer that is difficult to be uncovered to be clearly revealed, which will provide an available material and chemical method to investigate the structure-property relationship for gems as well as reveal the genesis of beautiful colors.
Comparison of Coulomb Impurity, Longitudinal Acoustic Phonons, and Surface Optical Phonons Affecting the n = 0 Landau Level in Monolayer Graphene
The influences of a charged Coulombic impurity with screened effect and carrier-phonon interaction on the n = 0 Landau level in monolayer graphene with a polar substrate under a high static magnetic field are discussed to compare the competition among the impurities, the longitudinal acoustic phonons in the graphene plane and the surface optical phonons on the substrate. A method of linear combination operators is used to deal with the position and momentum of a carrier in a magnetic field. The method of Lee-Low-Pines variation with an arbitrary carrier-phonon coupling is adopted to derive the effects of phonons. It is found that the energy gap of n = 0 Landau level opened by carrier-longitudinal acoustic phonons cannot be the main mechanism, whereas both the carrier-surface optical phonon interaction and the carrier-impurity interaction play the main roles in determining the energy splitting.