Investor Presentaiton
Unexpected finding #2: Graphene as reusable substrate
for bialkli photocathodes
Graphene
Active material
deposition
Thermal cleaning
at 500 °C
Silicon (Si) or
molybdenum (Mo)
8
New
7
Used
Quantum efficiency
QE[%]
CO
5
+
3
2
1
New
No residue
On other substrates
On graphene
Residue
(a) Graphene/Si
Silicon (Si) Molybdenum
@ 532 nm
(Mo)
Cs 4d
500°C
400°C
1
New
Graphene
4 cm
5
Used
Graphene Si
Substrates
Used
80
Binding Energy (eV)
(b) Graphene/Si
Si 2p (Oxide)
76
News released
(d) Si
Cs 4d
500°C
400°C
80
78
76
Binding Energy (eV)
(e) Si
Si 2p (Oxide)
(g) Mo
Cs 4d
(h) Mo
500°C
82
80
Binding Energy (ev)
78
76
Sb 4p
400°C
500°C
500°C
Si 2p (1/2 & 3/2)
400°C
Si 2p (1/2 & 3/2)
500°C
400°C
ح
400°C
105
102
99
96
93
102
99
93
105
102
99
93
90
Binding Energy (eV)
Binding Energy (eV)
Binding Energy (eV)
(c) Graphene/Si
(f) Si
(i) Mo
C 1s
C 1s
C 1s
300
K 2p
500°C
K 2p
500°C
400°C
400°C
297
294
288
297
291
288
297
294
291
288
285
Binding Energy (eV)
Binding Energy (eV)
Binding Energy (eV)
500°C
400°C
No detectable photocathode residue
on graphene by X-ray photoelectron spectroscopy
Mo
L.Guo et al. Appl. Phys. Lett. (2020)
11/8/2021 12View entire presentation