Variation of spectral response for exponential-doped transmission-mode GaAs photocathodes in the preparation process

Abstract

To confirm the actual effect of an exponential-doped structure on cathode performance, an exponential-doped structure was applied to the preparation of a transmission-mode GaAs photocathode, and spectral response curves after high-temperature activation, low-temperature activation, and the indium sealing process were separately measured by use of the on-line spectral response measurement system. The results show that, compared to the previously uniform-doped photocathode, the exponential-doped photocathode can obtain higher cathode performance and photoemission capability because of the built-in electric field. Nevertheless, cesium desorption and impurity of gas during the sealing process can cause the degeneration of spectral response in the entire response waveband, especially in the long-wavelength region, with the decrease in surface electron escape probability related to the adverse evolution of the surface potential barrier profile.

Comparative research on reflection-mode GaAs photocathode with graded AlxGa1−xAs buffer layer

“…Thus more photo-excited electrons will arrive at the back interface, the variation of S v has deep influence on the middle wavelength band. And the main improvement of graded structure for r-mode GaAs photocathode with thin active layer is the major optimization of S v , which will further increase the final quantum efficiency at middle wavelength band [15][16][17][18][19][20].…”

Comparative research for GaAs photocathodes with graded compositional Al x Ga 1−x As buffer layer

“…(1)-(3) cannot well fit the SRC curve for the mixed structure design for not taking the photo-excited electrons of window layer into consideration. The thorough well fitting equations for mixed structure design will be further deduced in later research [15][16][17][18][19][20].…”

Calibration of night vision goggles: an SI-units-based gain measurement technique

“…The GaAs photocathode is effective in the visible and near- IR ranges. Significant variations in responsivity, however, may be expected depending on the GaAs fabrication process [9,10]. The actual response of the photocathode (Fig.…”