Results 1 - 10 of 2250
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[en] We show that the optical excitation of multi-valley systems leads to valley currents which depend on the light polarization. The net electric current, determined by the vector sum of single-valley contributions, vanishes for some peculiar distributions of carriers in the valley and momentum spaces forming a pure valley current. We report on the study of this phenomenon, both experimental and theoretical, for graphene and 2D electron channels on the silicon surface
[en] Highlights: • We show a discrete Fe2TiO5-incorporation in hematite to improve the performance. • It can be well coupled with surface P-modification with a synergetic effect. • It shows a high photocurrent of 2.90 mA/cm2 at 1.23 VRHE with Co-Pi catalysts. • It provides a good insight to understand other Ti-based treatments of hematite. Hematite is a promising photocatalyst for solar water splitting while its performance has been severely limited by various factors. Recently surface Fe2TiO5 layer was widely reported to enhance the performance of hematite with a favorable band position to facilitate hole transport. Here we further show that the Fe2TiO5-incorporation in bulk hematite can also improve the performance with faster charge separation. Moreover, it can be well coupled with surface P-modification to simultaneously improve charge separation and hole transfer with a synergetic effect. The Ti and P co-modified hematite shows a significantly enhanced photocurrent of 2.37 mA/cm2 at 1.23 V vs. RHE when compared to the pristine value of 0.85 mA/cm2. After coupling with Co-Pi catalysts, the hematite sample can even achieve a stable, high photocurrent of 2.90 mA/cm2 at 1.23 V vs. RHE. The design of Ti and P co-modified hematite hollow nanostructures can be used as a promising candidate for solar water splitting applications. The discrete Fe2TiO5-incorporation also provides a good insight on the mechanism to understand other Ti-based treatments of hematite.
[en] A model for the photocurrent calculation in a Q D based solar cell is developed. It is shown that depending on the parameters and position of Q Ds inside the intrinsic region they can be both the generation and recombination centers
[en] A theoretical model is established to describe the emergence of the Meyer–Neldel rule (MNR) based on trap-limited current (TLC) theory. The model produces both MNR and anti-MNR behavior, and is available to various trap distributions. Moreover, TLC-based MNR is connected to persistent photocurrent (PPC) phenomenon. The information from MNR and PPC as well as their connection can be used to probe the distribution of the traps in materials. (paper)
[en] In this article the photoelectrical properties of In2O3-SiO2-Si-M structure was investigated. It was shown that in the wide wave interval (0,35-1 micro m) spectral characteristics strong dependence on applied voltage. The photocurrent amplification in the lower impedance In2O3-SiO2-Si-M structures was observed at the first time
[en] Graphene-based hybrid photo detectors are promising for weak-light detection with high photo gain. In this paper, we focused on the details of the scaling effect on grapheme-based hybrid photo detectors. By designing a series of devices with different sizes from 10*10μm2 to 100*100μm2, we found that the photocurrent generally decreases with increased channel length but decreased channel width. Our study would be useful for clarifying the real potential of photo gating effect in image applications. (paper)
[en] We show that when a monopolar current is passed through an n-i-n structure, superlinear photocurrent response occurs when there is a polariton condensate. This is in sharp contrast to the previously observed behavior for a standard semiconductor laser. Theoretical modeling shows that this is due to a stimulated exciton-exciton scattering process in which one exciton relaxes into the condensate, while another one dissociates into an electron-hole pair.
[en] The phthalocyanine(Pc) film can not be prepared by LB method because it is insoluble in organic solvents. In order to increase its solubility, two kinds of copper phthalocyanine derivatives (CuPc(COOH)2 and CuPc(COOH)4) were synthesized and their monolayers were prepared by LB method. It is found from the surface pressure-area curves that the LB monolayer film of CuPc(COOH)2 have more ordered structure than that of CuPc(COOH)4. In The photocurrent characteristic the value of CuPc(COOH)2 was superior to that of CuPc(COOH)4. Therefore, it is found that the charge generation efficiency for phthalocyanines have influenced on its ordered structure as the functional groups
[en] Highlights: • Large size and high quality MAPbI3 crystal grown from γ-butyrolactone. • An order enhanced photocurrents was observed on (112) plane. • (112) plane was more excellent in optoelectronic performances than (100) plane.