To enhance the quantum efficiency over the wavelength region of interest, a special graded band-gap structure applied to the AlGaAs/GaAs photocathodes is developed, in which the compositional grade in the AlxGa1−xAs layer is associated with the doping grade in the GaAs layer. The experimental results show that this unique structure can be achieved by the metalorganic chemical vapor deposition technique. As a result of the built-in electric fields arising from the graded band-gap structure, the quantum efficiency in the short-wavelength and long-wavelength regions is significantly increased for the transmission-mode and reflection-mode photocathodes, respectively.

1.
J.
Wehmeijer
and
B. V.
Geest
,
Nat. Photonics
4
,
152
(
2010
).
2.
B.
Smith
,
K.
Passmore
,
A.
Smith
,
R.
Lundberg
,
N.
Thomas
,
N.
Bell
,
C.
Lively
,
R.
Sillmon
,
R.
Benz
,
E.
Karplus
,
J.
Abraham
,
R.
Farrell
, and
D.
Ferenc
,
Nucl. Instrum. Methods Phys. Res. A
504
,
182
(
2003
).
3.
K.
Togawa
,
T.
Nakanishi
,
T.
Bada
,
F.
Furuta
,
H.
Horinaka
,
T.
Ida
,
Y.
Kurihara
,
H.
Matsumoto
,
T.
Matsuyama
,
M.
Mizuta
,
S.
Okumi
,
T.
Omori
,
C.
Suzuki
,
Y.
Takeuchi
,
K.
Wada
,
K.
Wada
, and
M.
Yoshioka
,
Nucl. Instrum. Methods Phys. Res. A
414
,
431
(
1998
).
4.
I. M.
Dharmadasa
,
J. S.
Roberts
, and
G.
Hill
,
Sol. Energy Mater. Sol. Cells
88
,
413
(
2005
).
5.
G.
Sassi
,
J. Appl. Phys.
54
,
5421
(
1983
).
6.
M.
Konagai
and
K.
Takahashi
,
Solid-State Electron.
19
,
259
(
1976
).
7.
A.
Moy
,
T.
Maruyama
,
F.
Zhou
, and
A.
Brachmann
,
AIP Conf. Proc.
1149
,
1038
(
2009
).
8.
L. B.
Jones
,
S. A.
Rozhkov
,
V. V.
Bakin
,
S. N.
Kosolobov
,
B. L.
Militsyn
,
H. E.
Scheibler
,
S. L.
Smith
, and
A. S.
Terekhov
,
AIP Conf. Proc.
1149
,
1057
(
2009
).
9.
J. J.
Zou
and
B. K.
Chang
,
Opt. Eng.
45
,
054001
(
2006
).
10.
Y. J.
Zhang
,
J.
Niu
,
J.
Zhao
,
J. J.
Zou
,
B. K.
Chang
,
F.
Shi
, and
H. C.
Cheng
,
J. Appl. Phys.
108
,
093108
(
2010
).
11.
D. G.
Fisher
,
R. E.
Enstrom
,
J. S.
Escher
,
H. F.
Gossenberger
, and
J. R.
Appert
,
IEEE Trans. Electron Devices
ED-21
,
641
(
1974
).
12.
T.
Maruyama
,
E. L.
Garwin
,
R. A.
Mair
,
R.
Prepost
,
J. S.
Smith
, and
J. D.
Walker
,
J. Appl. Phys.
73
,
5189
(
1993
).
13.
T.
Nishitani
,
M.
Tabuchi
,
Y.
Takeda
,
Y.
Suzuki
,
K.
Motoki
, and
T.
Meguro
,
Jpn. J. Appl. Phys.
48
,
06FF02
(
2009
).
14.
J.
Hu
and
R
Peng
,
Mater. Sci. Eng. B
30
,
39
(
1995
).
15.
G. A.
Antypas
,
J. S.
Escher
,
J.
Edgecumbe
, and
R. S.
Enck
, Jr.
,
J. Appl. Phys.
49
,
4301
(
1978
).
16.
Y.
Sun
,
Z.
Liu
,
P.
Pianetta
, and
D.
Lee
,
J. Appl. Phys.
102
,
074908
(
2007
).
You do not currently have access to this content.