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Time response measurement of pulsed electron beam from InGaN photocathode

Authors :
Daiki Sato
Haruka Shikano
Atsushi Koizumi
Tomohiro Nishitani
Source :
Journal of Vacuum Science & Technology B. 40:064204
Publication Year :
2022
Publisher :
American Vacuum Society, 2022.

Abstract

The photocurrent from a semiconductor photocathode with a negative-electron affinity surface can be arbitrarily controlled by the excitation laser power. Applying this characteristic to a scanning electron microscope allows the probe current to be arbitrarily controlled at any location on the sample. A photocathode with a fast time response is required to control the probe current at high speed. This study used an InGaN photocathode for pulsed electron beam generation and investigated its time response. A pulsed electron beam with 3.8 ns pulse width and 8.1 × 103 A cm−2 current density was observed, and the rise and fall times of the photocurrent were found to be 1.7 and 2.0 ns, respectively. The results show that despite the bottleneck of the time response of the laser power, the InGaN photocathode generates an electron beam that can control the probe current on a pixel-by-pixel for a 270 MHz scan speed.

Details

ISSN :
21662754 and 21662746
Volume :
40
Database :
OpenAIRE
Journal :
Journal of Vacuum Science & Technology B
Accession number :
edsair.doi...........781d1a5ce91dacf196a7a7e0e01f9cd1
Full Text :
https://doi.org/10.1116/6.0002122