Graphene Intermediate Layer for Robust and Spectrum-Extended Cu Photocathode Activated with Cs and O.

Developing an effective method to stably enhance the quantum efficiency (QE) and extend the photoemission threshold of Cu photocathodes beyond the ultraviolet region could benefit the photoinjector for ultrafast electron source applications. The implementation of a 2D material protective layer is considered a promising approach to extending the operating lifetime of photocathodes. We propose that graphene can serve as an intermediate layer at the interface between photocathode material and low-work-function coating.

Enhanced blue-green response of nanoarray AlGaAs photocathodes for underwater low-light detection.

Underwater optical communication and low-light detection are usually realized via blue-green laser sources and blue-green light-sensitive detectors. Negative-electron-affinity AlGaAs photocathode is an ideal photosensitive material for ocean exploration due to its adjustable spectrum range, long working lifetime, and easy epitaxy of materials. However, compared with other photocathodes, the main problem of AlGaAs photocathode is its low quantum efficiency.

Comparison of activation behavior of Cs-O and Cs-NF-adsorbed GaAs(100)-β(2 × 4) surface: From DFT simulation to experiment.

To clarify the performance differences between Cs-O and Cs-NF-activated GaAs photocathodes, the changes in adsorption characteristics with Cs coverage for the Cs-O and Cs-NF-adsorbed GaAs(100)-β(2 × 4) surfaces were investigated by first-principles calculation based on density function theory. The simulation results show that under the same Cs coverage, the Cs-NF-adsorbed GaAs surface is more stable than the Cs-only and Cs-O-adsorbed surfaces. In the case of small Cs coverage, the Cs-O-adsorbed GaAs surface exhibits a lower work function than Cs-NF does.

Denoising and Motion Artifact Removal Using Deformable Kernel Prediction Neural Network for Color-Intensified CMOS.

Image intensifiers are used internationally as advanced military night-vision devices. They have better imaging performance in low-light-level conditions than CMOS/CCD. The intensified CMOS (ICMOS) was developed to satisfy the digital demand of image intensifiers.

In situ characterization of thermal cleaned surface for preparing superior transmission-mode GaAs photocathodes.

Considering that it is impractical to utilize in situ surface diagnostic means to determine the surface cleanliness of transmission-mode GaAs photocathodes in the vacuum device manufacturing process, the thermal desorption technique with the aid of the quadrupole mass spectrometer during the thermal cleaning process is employed to in situ characterize the thermal cleaned surface. The desorption behaviors for various impurity gases during the thermal cleaning process are analyzed. The experimental results show that the amount of desorbed impurity gases varies due to the different heat treatment temperatures.

Comparative study of Al(x)Ga(1-x)As/GaAs photocathodes with different aluminum concentrations by surface photovoltage spectroscopy.

The influence of aluminum concentration in an Al(x)Ga(1-x)As window layer on the performance of Al(x)Ga(1-x)As/GaAs photocathodes was investigated. Three types of transmission-mode photocathode materials with different aluminum concentrations were designed for the comparative research. The surface photovoltage technique was applied to prepare samples.

Photoemission from advanced heterostructured Al(x)Ga(1-x)As/GaAs photocathodes under multilevel built-in electric field.

A heterostructured Al(x)Ga(1-x)As/GaAs photocathode consisting of a composition-graded buffer layer and an exponential-doped emission layer is developed to improve the photoemission performance over the wavelength region of interest. The theoretical quantum efficiency models for reflection-mode and transmission-mode Al(x)Ga(1-x)As/GaAs photocathodes are deduced based on one-dimensional continuity equations, respectively. By comparison of simulated results with conventional quantum efficiency models, it is found that the multilevel built-in electric field can effectively improve the quantum efficiency, which is related to the buffer layer parameters and cathode thicknesses.