scholarly journals Functional Integration of Catalysts with Si Nanowire Photocathodes for Efficient Utilization of Photogenerated Charge Carriers

ACS Omega ◽  
2021 ◽  
Author(s):  
Sung Yul Lim ◽  
Daye Seo ◽  
Min Seok Jang ◽  
Taek Dong Chung
2020 ◽  
Author(s):  
Changqiang Yu ◽  
Min Wen ◽  
Zhen Tong ◽  
Shuhua Li ◽  
Yanhong Yin ◽  
...  

    Photocatalysis is considered to be a green and promising technology for transforming organic contaminants into nontoxic products. In this work, the CuO/tourmaline composite with zero-dimensional/two-dimensional (0D/2D) CuO architecture was obtained via a facile hydrothermal process. CuO chemically interacted with tourmaline via Si-O-Cu bond. The specific surface area of the CuO/tourmaline composite (23.60 m2 g-1) was larger than that of pristine CuO (3.41 m2 g-1). Three predominant reactive species of superoxide radical (O2 •-), hydroxyl radical (•OH), and h+ were generated by the CuO/tourmaline composite aqueous suspension system under light irradiation. The CuO/tourmaline composite exhibited excellent photocatalytic capacity for the decomposition of organic pollutants, which was ascribed to the increase in the quantity of adsorption-photoreactive sites and the efficient utilization of photoinduced charge carriers benefited from tourmaline. This study offered a facile strategy for the construction of 0D/2D CuO structure and the design of tourmaline-based functional composite photocatalysts for the treatment of organic contaminants in waster.


2005 ◽  
Vol 19 (06) ◽  
pp. 929-970 ◽  
Author(s):  
M. E. PALISTRANT

The review of works about the study of the thermodynamic properties of the superconductors with energy bands overlapping on Fermi surface is done. The base of the review is Moscalenco's model1 with the formation of cooper pairs of electrons inside each energy band and their transition as a whole entity from one band to another. The model was generalized in order to consider the interband pairings of electrons in addition to the pairings that have been taken into account in Ref. 1. The main system of equations in this theory of superconductivity is derived for the two-band systems at arbitrary density of charge carriers (including the very low densities). The detailed studies of dependences of the temperature of superconducting transition TC, the jump of heat capacity (CS-CN), as well as the chemical potential μ on the density of charge carriers are made. Singularities in the behavior of the two-band superconductors at low densities of charge carriers (μ~TC) are revealed. There has been studies on the influence of the additional pairings of electrons that result in the formation of the cooper pairs of electrons from different energy bands on the thermodynamic properties of the system. Both phonon and non-phonon mechanisms of superconductivity in the BCS scenario of the formation of superconducting pairs (μ>0) have been taken into account. The theory of superconductivity in the mean-field approximation at T = 0 in the picture of Bose condensation of localized pairs (Schaffroth's scenario μ<0) is built. The technique of functional integration with regard to the two-band system is developed and the crossover from Fermi to Bose picture of elementary excitations at T≠0 with the two-particle bound state in the system has been shown. The temperature of Bose condensation TK is determined and the influence of the overlapping of energy bands on Fermi surface onto Bose condensation of localized pairs is studied.


Author(s):  
Klaus-Ruediger Peters

Environmental SEM operate at specimen chamber pressures of ∼20 torr (2.7 kPa) allowing stabilization of liquid water at room temperature, working on rugged insulators, and generation of an environmental secondary electron (ESE) signal. All signals available in conventional high vacuum instruments are also utilized in the environmental SEM, including BSE, SE, absorbed current, CL, and X-ray. In addition, the ESEM allows utilization of the flux of charge carriers as information, providing exciting new signal modes not available to BSE imaging or to conventional high vacuum SEM.In the ESEM, at low vacuum, SE electrons are collected with a “gaseous detector”. This detector collects low energy electrons (and ions) with biased wires or plates similar to those used in early high vacuum SEM for SE detection. The detector electrode can be integrated into the first PLA or positioned at any other place resulting in a versatile system that provides a variety of surface information.


Author(s):  
Yimei Zhu ◽  
J. Tafto

The electron holes confined to the CuO2-plane are the charge carriers in high-temperature superconductors, and thus, the distribution of charge plays a key role in determining their superconducting properties. While it has been known for a long time that in principle, electron diffraction at low angles is very sensitive to charge transfer, we, for the first time, show that under a proper TEM imaging condition, it is possible to directly image charge in crystals with a large unit cell. We apply this new way of studying charge distribution to the technologically important Bi2Sr2Ca1Cu2O8+δ superconductors.Charged particles interact with the electrostatic potential, and thus, for small scattering angles, the incident particle sees a nuclei that is screened by the electron cloud. Hence, the scattering amplitude mainly is determined by the net charge of the ion. Comparing with the high Z neutral Bi atom, we note that the scattering amplitude of the hole or an electron is larger at small scattering angles. This is in stark contrast to the displacements which contribute negligibly to the electron diffraction pattern at small angles because of the short g-vectors.


Author(s):  
Marc H. Peeters ◽  
Max T. Otten

Over the past decades, the combination of energy-dispersive analysis of X-rays and scanning electron microscopy has proved to be a powerful tool for fast and reliable elemental characterization of a large variety of specimens. The technique has evolved rapidly from a purely qualitative characterization method to a reliable quantitative way of analysis. In the last 5 years, an increasing need for automation is observed, whereby energy-dispersive analysers control the beam and stage movement of the scanning electron microscope in order to collect digital X-ray images and perform unattended point analysis over multiple locations.The Philips High-speed Analysis of X-rays system (PHAX-Scan) makes use of the high performance dual-processor structure of the EDAX PV9900 analyser and the databus structure of the Philips series 500 scanning electron microscope to provide a highly automated, user-friendly and extremely fast microanalysis system. The software that runs on the hardware described above was specifically designed to provide the ultimate attainable speed on the system.


2002 ◽  
Vol 719 ◽  
Author(s):  
Galina Khlyap

AbstractRoom-temperature electric investigations carried out in CO2-laser irradiated ZnCdHgTe epifilms revealed current-voltage and capacitance-voltage dependencies typical for the metal-semiconductor barrier structure. The epilayer surface studies had demonstrated that the cell-like relief has replaced the initial tessellated structure observed on the as-grown samples. The detailed numerical analysis of the experimental measurements and morphological investigations of the film surface showed that the boundaries of the cells formed under the laser irradiation are appeared as the regions of accumulation of derived charged defects of different type of conductivity supplying free charge carriers under the applied electric field.


2003 ◽  
Vol 771 ◽  
Author(s):  
Michael C. Hamilton ◽  
Sandrine Martin ◽  
Jerzy Kanicki

AbstractWe have investigated the effects of white-light illumination on the electrical performance of organic polymer thin-film transistors (OP-TFTs). The OFF-state drain current is significantly increased, while the drain current in the strong accumulation regime is relatively unaffected. At the same time, the threshold voltage is decreased and the subthreshold slope is increased, while the field-effect mobility of the charge carriers is not affected. The observed effects are explained in terms of the photogeneration of free charge carriers in the channel region due to the absorbed photons.


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