The surface photovoltage (SPV) spectrum due to subband‐gap illumination of thin films is theoretically studied. It is shown that this SPV is inherently sensitive to buried interfaces just as it is sensitive to the external semiconductor surface. The different contributions to the SPV from all the optically active gap states present within a sample, consisting of a bulk substrate covered by a thin film, are analyzed. Analytical expressions are obtained in the low illumination intensity and the depletion approximation regime. The evolution of the SPV spectrum with film thickness is examined and is found to depend on both site and population of the gap states. Three modes of evolution are found, according to the relative importance of gap state population changes with film thickness. These modes are confirmed by a numerical simulation of a thin film of pseudomorphic InAlAs on InP substrates and by experiments conducted on the same system. The approach is also applied to the InP/In2O3 system, revealing gap state formation, followed by filling with electrons, thereby explaining previous observations of nearly ideal IV behavior at this junction.

1.
C. W. Wilmsen, Physics and Chemistry of III–V Semiconductor Interfaces (Plenum, New York, 1985).
2.
Metal–Semiconductor Schottky Barrier Junctions and Their Applications, edited by B. L. Sharma (Plenum, New York, 1984).
3.
H. C.
Gatos
and
J.
Lagowski
,
J. Vac. Sci. Technol.
10
,
130
(
1973
).
4.
L.
Kronik
,
M.
Leibovitch
,
E.
Fefer
,
L.
Burstein
, and
Y.
Shapira
,
J. Electron. Mater.
24
,
379
(
1995
).
5.
M.
Leibovitch
,
L.
Kronik
,
E.
Fefer
, and
Y.
Shapira
,
Phys. Rev. B
50
,
1739
(
1994
).
6.
W.
Shockley
and
W. T.
Read
,
Phys. Rev.
87
,
835
(
1952
).
7.
G.
Ashkinazi
,
M.
Leibovitch
, and
M.
Nathan
,
IEEE Trans. Electron Devices
ED-40
,
285
(
1993
).
8.
Data taken from Semiconductors: Group IV Elements and III–V Compounds, edited by O. Madelung, Data Series in Science and Technology (Springer, Berlin, 1991).
9.
P. T. Greiling, in Proceedings of the 6th International Conference on InP and Related Materials, Santa Barbara, CA, 1994, p. 3.
10.
I.
Hamberg
and
C. G.
Granqvist
,
J. Appl. Phys.
60
,
R123
(
1986
).
11.
P.
Chu
,
C. L.
Lin
, and
H. H.
Wieder
,
Appl. Phys. Lett.
53
,
2423
(
1988
).
12.
L.
Burstein
,
Y.
Shapira
,
B. R.
Bennet
, and
J. A.
del Alamo
,
J. Appl. Phys.
78
,
7613
(
1995
).
13.
V.
Korobov
,
M.
Leibovitch
, and
Y.
Shapira
,
J. Appl. Phys.
74
,
3251
(
1993
).
14.
V.
Korobov
,
Y.
Shapira
,
B.
Ber
,
K.
Faleev
, and
D.
Zushinskiy
,
J. Appl. Phys.
75
,
2264
(
1994
).
This content is only available via PDF.
You do not currently have access to this content.