Share Email Print

Proceedings Paper

MBE-grown InGaAs photocathodes
Author(s): Loig E. Bourree; David R. Chasse; P.L. Stephan Thamban; Robert Glosser
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

The material constitution of modern photocathodes (i.e. third generation) has remained a constant for almost two decades. The active GaAs layer is grown by metal organic chemical vapor deposition (MOCVD) and processed to create a negative electron affinity (NEA) surface for photoemission. Thus, these types of cathodes are limited in their spectral response by the band gap energy of the GaAs. There is interest in extending this range past 1000nm while preserving a high quantum efficiency (QE). This would allow taking advantage of an increased luminescence of night sky in the infrared. MOCVD grown InGaAs photocathodes have a photoresponse (PR) in the near infrared. Still, a major drawback to date has been its low QE. We believe that the use of molecular beam epitaxy (MBE) to grow this alloy will permit the fabrication of a higher quality device beyond today's standards, with improved equivalent background illumination and higher QE over a 700nm to 1100nm spectral range. To demonstrate this concept two reflection mode InGaAs photocathode were grown. These cathodes were NEA activated with Cs:O in situ in the MBE reactor after their growth and their PR recorded. Following the activation, optical characterization techniques (i.e. photoluminescence, Raman spectroscopy) were employed to probe electron and phonon energy to relate fundamental material parameters to the observed PR. The collected information is being used to correct and enhance growth characteristics to increase spectral response and QE.

Paper Details

Date Published: 5 February 2003
PDF: 10 pages
Proc. SPIE 4796, Low-Light-Level and Real-Time Imaging Systems, Components, and Applications, (5 February 2003); doi: 10.1117/12.450884
Show Author Affiliations
Loig E. Bourree, Univ. of Texas at Dallas (United States)
David R. Chasse, MBE Specialist (United States)
P.L. Stephan Thamban, Univ. of Texas at Dallas (United States)
Robert Glosser, Univ. of Texas at Dallas (United States)

Published in SPIE Proceedings Vol. 4796:
Low-Light-Level and Real-Time Imaging Systems, Components, and Applications
C. Bruce Johnson; Divyendu Sinha; Phillip A. Laplante, Editor(s)

© SPIE. Terms of Use
Back to Top