Photocathode R

1
Photocathode RD

• Saxet SBIR
• Tested new cathode platter and Ta-disk using AXT
  bulk GaAs
• The new contactor assembly is delivered.
• New Cesiator is being made.

2
QE comparison of IQE wafer and AXT bulk GaAs
The steeper QE drop in the IQE sample can be
explained by the conduction band energy barrier.
3

• SBIR Phase I approved to develop
  strained-superlattice GaAs-InGaP
• 100 K (20 K to SLAC) over 6 9 months
• Strained Wells or Strained Barriers

Strained Barriers
Strained Wells
1) GaAs cap 2) In(0.62)Ga(0.38)P 3) GaAs
repeat 2) and 3) 4) In(0.48)Ga(0.52)P 5) GaAs sub
1) GaAs cap 2) In(0.35)Ga(0.65)P 3) GaAs
repeat 2) and 3) 4) In(0.35)Ga(0.65)P 2.5 um 5)
In(x)Ga(1-x)P x 0.48 -gt 0.35 6)
In(0.48)Ga(0.52)P 7) GaAs sub