Abstract

We compared two reflection-mode negative electron affinity (NEA) GaAs photocathode samples that are grown by molecular beam epitaxy with p-type beryllium doping. One sample is uniform doping, and another is gradient doping. Experimental curves of spectral response sensitivity and quantum efficiency are obtained. The thicknesses of the two cathodes are both 2.6  μm. The integrated sensitivity of the uniform doping one is 1966  μA/lm, and that of the gradient-doping one is 2421μA/lm. The escape probability and diffusion length are fitted from the spectral response curves. For the uniform-doping sample, the escape probability is 0.45 and the diffusion length is 5  μm. For the gradient-doping sample, the escape probability is 0.55 and the diffusion length is 5 .5   μm.

© 2007 Optical Society of America

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  1. G. A. Mulhollan, A. V. Subashiev, J. E. Clendenin, E. L. Garwin, R. E. Kirby, T. Maruyama, and R. Prepost, "High performance polarized electron photocathodes based on InGaAl/AlGaAAs superlattices," Phys. Lett. A 282, 309-318 (2001).
    [CrossRef]
  2. H.-J. Drouhin, C. Hermann, and G. Lampel, "Photoemission from activated gallium arsenide. 1. Very-high-resolution energy distribution curves," Phys. Rev. B 31, 3859-3871 (1985).
    [CrossRef]
  3. T. Maruyama, A. Brachmann, J. E. Clendenin, T. Desikan, E. L. Garwin, R. E. Kirby, D.-A. Luh, J. Turner, and R. Prepost, "A very high charge, high polarization gradient-doped strained GaAs photocathode," Nucl. Instrum. Methods Phys. Res. A 492, 199-211 (2002).
    [CrossRef]
  4. Liu Lei and Chang Benkang, "Spectral matching factors between Super S-25 and New S-25 photocathodes and reflective radiation of objects," Appl. Opt. 43, 616-619 (2004).
    [CrossRef]
  5. L. W. James, G. A. Antypas, J. Edgecumbe, R. L. Moon, and R. L. Bell, "Dependence on crystalline face of the band bending in Cs20-activated GaAs," J. Appl. Phys. 42, 4976-4980 (1971).
    [CrossRef]
  6. Lihui Guo, Jinmin Li, and Hou Xun, "The quantum efficiency of field-assisted transmission-mode GaAs photocathodes," J. Phys. D 22, 348-353 (1989).
    [CrossRef]
  7. Y. Z. Liu, J. L. Moll, and W. E. Spicer, "Quantum yield of GaAs semitransparent photocathode," Appl. Phys. Lett. 17, 60-62 (1970).
    [CrossRef]
  8. G. Vergara, L. J. Gomez, J. Capmany, and M. T. Montojo, "Influence of the dopant concentration on the photoemission in the NEA GaAs photocathodes," Vacuum 48, 155-160 (1997).
    [CrossRef]
  9. X. Q. Du and B. K. Chang, "Angle-dependent XPS study of the mechanism of "high-low temperature activation of GaAs photocathode," Appl. Surf. Sci. 251, 267-272 (2005).
    [CrossRef]
  10. C. Y. Su, W. E. Spicer, and I. Lindau, "Photoelectron spectroscopic determination of the structure of (Cs, O) activated GaAs (110) surface," J. Appl. Phys. 54, 1413-1422 (1983).
    [CrossRef]

2005

X. Q. Du and B. K. Chang, "Angle-dependent XPS study of the mechanism of "high-low temperature activation of GaAs photocathode," Appl. Surf. Sci. 251, 267-272 (2005).
[CrossRef]

2004

2002

T. Maruyama, A. Brachmann, J. E. Clendenin, T. Desikan, E. L. Garwin, R. E. Kirby, D.-A. Luh, J. Turner, and R. Prepost, "A very high charge, high polarization gradient-doped strained GaAs photocathode," Nucl. Instrum. Methods Phys. Res. A 492, 199-211 (2002).
[CrossRef]

2001

G. A. Mulhollan, A. V. Subashiev, J. E. Clendenin, E. L. Garwin, R. E. Kirby, T. Maruyama, and R. Prepost, "High performance polarized electron photocathodes based on InGaAl/AlGaAAs superlattices," Phys. Lett. A 282, 309-318 (2001).
[CrossRef]

1997

G. Vergara, L. J. Gomez, J. Capmany, and M. T. Montojo, "Influence of the dopant concentration on the photoemission in the NEA GaAs photocathodes," Vacuum 48, 155-160 (1997).
[CrossRef]

1989

Lihui Guo, Jinmin Li, and Hou Xun, "The quantum efficiency of field-assisted transmission-mode GaAs photocathodes," J. Phys. D 22, 348-353 (1989).
[CrossRef]

1985

H.-J. Drouhin, C. Hermann, and G. Lampel, "Photoemission from activated gallium arsenide. 1. Very-high-resolution energy distribution curves," Phys. Rev. B 31, 3859-3871 (1985).
[CrossRef]

1983

C. Y. Su, W. E. Spicer, and I. Lindau, "Photoelectron spectroscopic determination of the structure of (Cs, O) activated GaAs (110) surface," J. Appl. Phys. 54, 1413-1422 (1983).
[CrossRef]

1971

L. W. James, G. A. Antypas, J. Edgecumbe, R. L. Moon, and R. L. Bell, "Dependence on crystalline face of the band bending in Cs20-activated GaAs," J. Appl. Phys. 42, 4976-4980 (1971).
[CrossRef]

1970

Y. Z. Liu, J. L. Moll, and W. E. Spicer, "Quantum yield of GaAs semitransparent photocathode," Appl. Phys. Lett. 17, 60-62 (1970).
[CrossRef]

Antypas, G. A.

L. W. James, G. A. Antypas, J. Edgecumbe, R. L. Moon, and R. L. Bell, "Dependence on crystalline face of the band bending in Cs20-activated GaAs," J. Appl. Phys. 42, 4976-4980 (1971).
[CrossRef]

Bell, R. L.

L. W. James, G. A. Antypas, J. Edgecumbe, R. L. Moon, and R. L. Bell, "Dependence on crystalline face of the band bending in Cs20-activated GaAs," J. Appl. Phys. 42, 4976-4980 (1971).
[CrossRef]

Benkang, Chang

Brachmann, A.

T. Maruyama, A. Brachmann, J. E. Clendenin, T. Desikan, E. L. Garwin, R. E. Kirby, D.-A. Luh, J. Turner, and R. Prepost, "A very high charge, high polarization gradient-doped strained GaAs photocathode," Nucl. Instrum. Methods Phys. Res. A 492, 199-211 (2002).
[CrossRef]

Capmany, J.

G. Vergara, L. J. Gomez, J. Capmany, and M. T. Montojo, "Influence of the dopant concentration on the photoemission in the NEA GaAs photocathodes," Vacuum 48, 155-160 (1997).
[CrossRef]

Chang, B. K.

X. Q. Du and B. K. Chang, "Angle-dependent XPS study of the mechanism of "high-low temperature activation of GaAs photocathode," Appl. Surf. Sci. 251, 267-272 (2005).
[CrossRef]

Clendenin, J. E.

T. Maruyama, A. Brachmann, J. E. Clendenin, T. Desikan, E. L. Garwin, R. E. Kirby, D.-A. Luh, J. Turner, and R. Prepost, "A very high charge, high polarization gradient-doped strained GaAs photocathode," Nucl. Instrum. Methods Phys. Res. A 492, 199-211 (2002).
[CrossRef]

G. A. Mulhollan, A. V. Subashiev, J. E. Clendenin, E. L. Garwin, R. E. Kirby, T. Maruyama, and R. Prepost, "High performance polarized electron photocathodes based on InGaAl/AlGaAAs superlattices," Phys. Lett. A 282, 309-318 (2001).
[CrossRef]

Desikan, T.

T. Maruyama, A. Brachmann, J. E. Clendenin, T. Desikan, E. L. Garwin, R. E. Kirby, D.-A. Luh, J. Turner, and R. Prepost, "A very high charge, high polarization gradient-doped strained GaAs photocathode," Nucl. Instrum. Methods Phys. Res. A 492, 199-211 (2002).
[CrossRef]

Drouhin, H.-J.

H.-J. Drouhin, C. Hermann, and G. Lampel, "Photoemission from activated gallium arsenide. 1. Very-high-resolution energy distribution curves," Phys. Rev. B 31, 3859-3871 (1985).
[CrossRef]

Du, X. Q.

X. Q. Du and B. K. Chang, "Angle-dependent XPS study of the mechanism of "high-low temperature activation of GaAs photocathode," Appl. Surf. Sci. 251, 267-272 (2005).
[CrossRef]

Edgecumbe, J.

L. W. James, G. A. Antypas, J. Edgecumbe, R. L. Moon, and R. L. Bell, "Dependence on crystalline face of the band bending in Cs20-activated GaAs," J. Appl. Phys. 42, 4976-4980 (1971).
[CrossRef]

Garwin, E. L.

T. Maruyama, A. Brachmann, J. E. Clendenin, T. Desikan, E. L. Garwin, R. E. Kirby, D.-A. Luh, J. Turner, and R. Prepost, "A very high charge, high polarization gradient-doped strained GaAs photocathode," Nucl. Instrum. Methods Phys. Res. A 492, 199-211 (2002).
[CrossRef]

G. A. Mulhollan, A. V. Subashiev, J. E. Clendenin, E. L. Garwin, R. E. Kirby, T. Maruyama, and R. Prepost, "High performance polarized electron photocathodes based on InGaAl/AlGaAAs superlattices," Phys. Lett. A 282, 309-318 (2001).
[CrossRef]

Gomez, L. J.

G. Vergara, L. J. Gomez, J. Capmany, and M. T. Montojo, "Influence of the dopant concentration on the photoemission in the NEA GaAs photocathodes," Vacuum 48, 155-160 (1997).
[CrossRef]

Guo, Lihui

Lihui Guo, Jinmin Li, and Hou Xun, "The quantum efficiency of field-assisted transmission-mode GaAs photocathodes," J. Phys. D 22, 348-353 (1989).
[CrossRef]

Hermann, C.

H.-J. Drouhin, C. Hermann, and G. Lampel, "Photoemission from activated gallium arsenide. 1. Very-high-resolution energy distribution curves," Phys. Rev. B 31, 3859-3871 (1985).
[CrossRef]

James, L. W.

L. W. James, G. A. Antypas, J. Edgecumbe, R. L. Moon, and R. L. Bell, "Dependence on crystalline face of the band bending in Cs20-activated GaAs," J. Appl. Phys. 42, 4976-4980 (1971).
[CrossRef]

Kirby, R. E.

T. Maruyama, A. Brachmann, J. E. Clendenin, T. Desikan, E. L. Garwin, R. E. Kirby, D.-A. Luh, J. Turner, and R. Prepost, "A very high charge, high polarization gradient-doped strained GaAs photocathode," Nucl. Instrum. Methods Phys. Res. A 492, 199-211 (2002).
[CrossRef]

G. A. Mulhollan, A. V. Subashiev, J. E. Clendenin, E. L. Garwin, R. E. Kirby, T. Maruyama, and R. Prepost, "High performance polarized electron photocathodes based on InGaAl/AlGaAAs superlattices," Phys. Lett. A 282, 309-318 (2001).
[CrossRef]

Lampel, G.

H.-J. Drouhin, C. Hermann, and G. Lampel, "Photoemission from activated gallium arsenide. 1. Very-high-resolution energy distribution curves," Phys. Rev. B 31, 3859-3871 (1985).
[CrossRef]

Lei, Liu

Li, Jinmin

Lihui Guo, Jinmin Li, and Hou Xun, "The quantum efficiency of field-assisted transmission-mode GaAs photocathodes," J. Phys. D 22, 348-353 (1989).
[CrossRef]

Lindau, I.

C. Y. Su, W. E. Spicer, and I. Lindau, "Photoelectron spectroscopic determination of the structure of (Cs, O) activated GaAs (110) surface," J. Appl. Phys. 54, 1413-1422 (1983).
[CrossRef]

Liu, Y. Z.

Y. Z. Liu, J. L. Moll, and W. E. Spicer, "Quantum yield of GaAs semitransparent photocathode," Appl. Phys. Lett. 17, 60-62 (1970).
[CrossRef]

Luh, D.-A.

T. Maruyama, A. Brachmann, J. E. Clendenin, T. Desikan, E. L. Garwin, R. E. Kirby, D.-A. Luh, J. Turner, and R. Prepost, "A very high charge, high polarization gradient-doped strained GaAs photocathode," Nucl. Instrum. Methods Phys. Res. A 492, 199-211 (2002).
[CrossRef]

Maruyama, T.

T. Maruyama, A. Brachmann, J. E. Clendenin, T. Desikan, E. L. Garwin, R. E. Kirby, D.-A. Luh, J. Turner, and R. Prepost, "A very high charge, high polarization gradient-doped strained GaAs photocathode," Nucl. Instrum. Methods Phys. Res. A 492, 199-211 (2002).
[CrossRef]

G. A. Mulhollan, A. V. Subashiev, J. E. Clendenin, E. L. Garwin, R. E. Kirby, T. Maruyama, and R. Prepost, "High performance polarized electron photocathodes based on InGaAl/AlGaAAs superlattices," Phys. Lett. A 282, 309-318 (2001).
[CrossRef]

Moll, J. L.

Y. Z. Liu, J. L. Moll, and W. E. Spicer, "Quantum yield of GaAs semitransparent photocathode," Appl. Phys. Lett. 17, 60-62 (1970).
[CrossRef]

Montojo, M. T.

G. Vergara, L. J. Gomez, J. Capmany, and M. T. Montojo, "Influence of the dopant concentration on the photoemission in the NEA GaAs photocathodes," Vacuum 48, 155-160 (1997).
[CrossRef]

Moon, R. L.

L. W. James, G. A. Antypas, J. Edgecumbe, R. L. Moon, and R. L. Bell, "Dependence on crystalline face of the band bending in Cs20-activated GaAs," J. Appl. Phys. 42, 4976-4980 (1971).
[CrossRef]

Mulhollan, G. A.

G. A. Mulhollan, A. V. Subashiev, J. E. Clendenin, E. L. Garwin, R. E. Kirby, T. Maruyama, and R. Prepost, "High performance polarized electron photocathodes based on InGaAl/AlGaAAs superlattices," Phys. Lett. A 282, 309-318 (2001).
[CrossRef]

Prepost, R.

T. Maruyama, A. Brachmann, J. E. Clendenin, T. Desikan, E. L. Garwin, R. E. Kirby, D.-A. Luh, J. Turner, and R. Prepost, "A very high charge, high polarization gradient-doped strained GaAs photocathode," Nucl. Instrum. Methods Phys. Res. A 492, 199-211 (2002).
[CrossRef]

G. A. Mulhollan, A. V. Subashiev, J. E. Clendenin, E. L. Garwin, R. E. Kirby, T. Maruyama, and R. Prepost, "High performance polarized electron photocathodes based on InGaAl/AlGaAAs superlattices," Phys. Lett. A 282, 309-318 (2001).
[CrossRef]

Spicer, W. E.

C. Y. Su, W. E. Spicer, and I. Lindau, "Photoelectron spectroscopic determination of the structure of (Cs, O) activated GaAs (110) surface," J. Appl. Phys. 54, 1413-1422 (1983).
[CrossRef]

Y. Z. Liu, J. L. Moll, and W. E. Spicer, "Quantum yield of GaAs semitransparent photocathode," Appl. Phys. Lett. 17, 60-62 (1970).
[CrossRef]

Su, C. Y.

C. Y. Su, W. E. Spicer, and I. Lindau, "Photoelectron spectroscopic determination of the structure of (Cs, O) activated GaAs (110) surface," J. Appl. Phys. 54, 1413-1422 (1983).
[CrossRef]

Subashiev, A. V.

G. A. Mulhollan, A. V. Subashiev, J. E. Clendenin, E. L. Garwin, R. E. Kirby, T. Maruyama, and R. Prepost, "High performance polarized electron photocathodes based on InGaAl/AlGaAAs superlattices," Phys. Lett. A 282, 309-318 (2001).
[CrossRef]

Turner, J.

T. Maruyama, A. Brachmann, J. E. Clendenin, T. Desikan, E. L. Garwin, R. E. Kirby, D.-A. Luh, J. Turner, and R. Prepost, "A very high charge, high polarization gradient-doped strained GaAs photocathode," Nucl. Instrum. Methods Phys. Res. A 492, 199-211 (2002).
[CrossRef]

Vergara, G.

G. Vergara, L. J. Gomez, J. Capmany, and M. T. Montojo, "Influence of the dopant concentration on the photoemission in the NEA GaAs photocathodes," Vacuum 48, 155-160 (1997).
[CrossRef]

Xun, Hou

Lihui Guo, Jinmin Li, and Hou Xun, "The quantum efficiency of field-assisted transmission-mode GaAs photocathodes," J. Phys. D 22, 348-353 (1989).
[CrossRef]

Appl. Opt.

Appl. Phys. Lett.

Y. Z. Liu, J. L. Moll, and W. E. Spicer, "Quantum yield of GaAs semitransparent photocathode," Appl. Phys. Lett. 17, 60-62 (1970).
[CrossRef]

Appl. Surf. Sci.

X. Q. Du and B. K. Chang, "Angle-dependent XPS study of the mechanism of "high-low temperature activation of GaAs photocathode," Appl. Surf. Sci. 251, 267-272 (2005).
[CrossRef]

J. Appl. Phys.

C. Y. Su, W. E. Spicer, and I. Lindau, "Photoelectron spectroscopic determination of the structure of (Cs, O) activated GaAs (110) surface," J. Appl. Phys. 54, 1413-1422 (1983).
[CrossRef]

L. W. James, G. A. Antypas, J. Edgecumbe, R. L. Moon, and R. L. Bell, "Dependence on crystalline face of the band bending in Cs20-activated GaAs," J. Appl. Phys. 42, 4976-4980 (1971).
[CrossRef]

J. Phys. D

Lihui Guo, Jinmin Li, and Hou Xun, "The quantum efficiency of field-assisted transmission-mode GaAs photocathodes," J. Phys. D 22, 348-353 (1989).
[CrossRef]

Nucl. Instrum. Methods Phys. Res. A

T. Maruyama, A. Brachmann, J. E. Clendenin, T. Desikan, E. L. Garwin, R. E. Kirby, D.-A. Luh, J. Turner, and R. Prepost, "A very high charge, high polarization gradient-doped strained GaAs photocathode," Nucl. Instrum. Methods Phys. Res. A 492, 199-211 (2002).
[CrossRef]

Phys. Lett. A

G. A. Mulhollan, A. V. Subashiev, J. E. Clendenin, E. L. Garwin, R. E. Kirby, T. Maruyama, and R. Prepost, "High performance polarized electron photocathodes based on InGaAl/AlGaAAs superlattices," Phys. Lett. A 282, 309-318 (2001).
[CrossRef]

Phys. Rev. B

H.-J. Drouhin, C. Hermann, and G. Lampel, "Photoemission from activated gallium arsenide. 1. Very-high-resolution energy distribution curves," Phys. Rev. B 31, 3859-3871 (1985).
[CrossRef]

Vacuum

G. Vergara, L. J. Gomez, J. Capmany, and M. T. Montojo, "Influence of the dopant concentration on the photoemission in the NEA GaAs photocathodes," Vacuum 48, 155-160 (1997).
[CrossRef]

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Figures (4)

Fig. 1
Fig. 1

Blocking of multiinformation measurement system.

Fig. 2
Fig. 2

Doping structure of (a) sample A and (b) sample B.

Fig. 3
Fig. 3

(a) Spectral response curves and (b) quantum response curves of two activated samples.

Fig. 4
Fig. 4

Band structure and surface potential barrier of NEA GaAs photocathodes:(a) uniform-doping NEA GaAs and (b) gradient-doping NEA GaAs. E C is the conduction band minimum, E V is the valence band peak level, E g is the width of the bandgap, E F is the Fermi level, and δ S is the height of the surface band bending.

Tables (2)

Tables Icon

Table 1 Spectral Response Property Parameters and Sensitivity of Curves

Tables Icon

Table 2 Data Fitting Results of Spectral Curves

Equations (64)

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2.6   μm
1966   μA / lm
2421 μA / lm
5   μm
5 .5   μm
W = ( 2 ε V BB / q N A ) 1 / 2 ,
V BB
N A
c m 3
N A
800
910   nm
d 2 n / d x 2 n / L D 2 = g ( x ) / D n ,
D n
L D
g ( x )
g ( x ) = ( 1 R ) I 0 exp ( α x ) ,
I 0
n ( x ) = C 1 exp ( x L D ) + C 2 exp ( x L D ) + τ 1 α 2 L D 2 g ( x ) ,
C 1
C 2
L D = ( D / τ ) 1 / 2
C 1
C 2
n ( x ) | x = 0 = 0 , n ( x ) | x = = 0 .
n ( x ) = α ( 1 R ) L D 2 I 0 ( 1 α 2 L D 2 ) D n [ exp ( α x ) exp ( x L D ) ] .
Y r = P D n d n d x | X = 0 I 0 .
Y r = P ( 1 R ) 1 + 1 / α L D .
L D
800
800
910   nm
L D
L D = ( D n τ ) 1 / 2 ,
D n
D n = ( k T / q ) μ n ,
μ n
μ n
μ n T 3 / 2 / N A ,
N A
N A
D n
D 1
q V D 1 = E F 1 E F 2 = ( E V + k T ln N V N A 1 ) ( E V + k T ln N V N A 2 )
= k T ln N A 2 N A 1 ,
E F 1
N A 1
E F 2
N A 2
N A 1 > N A 2
E V
N V
D 1
W D 1 = ( 2 ε 0 ε V D 1 q N A 1 ) 1 / 2 .
D 1
E 1 = V D 1 W D 1 .
0.059   eV
1966   μA / lm
2421 μA / lm
E C
E V
E g
E F
δ S

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