US 12,437,954 B2
Substrate stack epitaxies for photocathodes for extended wavelengths
Bed Pantha, Chandler, AZ (US); Jacob J. Becker, Gilbert, AZ (US); and Jon D. Burnsed, Tempe, AZ (US)
Assigned to L3HARRIS TECHNOLOGIES, INC., Melbourne, FL (US)
Filed by L3Harris Technologies, Inc., Melbourne, FL (US)
Filed on Nov. 2, 2022, as Appl. No. 17/979,639.
Prior Publication US 2024/0145202 A1, May 2, 2024
Int. Cl. H01J 1/34 (2006.01); H01J 9/12 (2006.01)
CPC H01J 1/34 (2013.01) [H01J 9/12 (2013.01); H01J 2201/3423 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A photocathode epitaxial structure comprising:
an improved substrate stack, the improved substrate stack comprising:
a GaAs substrate; and
one or more additional layers formed on the GaAs substrate, the one or more additional layers configured to provide an improved substrate stack surface with predetermined characteristics for forming a semiconductor device on the improved substrate stack surface; and
an InGaAs p-type photocathode formed on the improved substrate stack surface, the InGaAs p-type photocathode having a predetermined percentage of In,
wherein the improved substrate comprises an overshoot layer having a first amount of Indium doping that is greater than second amount of doping in the InGaAs p-type photocathode to reduce strain.