The kinetics of the photodarkening effect has been studied experimentally for amorphous selenium (a-Se) layers at room temperature and at an elevated temperature (35°C) close to the glass transition. By switching an intense pumping light on and off with a period of 100s, we have studied the kinetics of both the buildup of photodarkening and its relaxation (recovery). It was found that at 35°C, only a reversible component of photodarkening has been observed. This result has been interpreted within the framework of a phenomenological model assuming that photodarkening is caused by light-induced transitions of structural units from their ground states into metastable states. Our estimate for the energy barrier EB between these states obtained for the photodarkening process (EB0.8eV) coincides with that obtained from the analysis of the relaxation process. At room temperature, an irreversible component of photodarkening has been observed along with the reversible one. The energy barrier responsible for the relaxation of the reversible component at room temperature appears the same as at 35°C. This suggests that the energy barrier identified represents a fundamental feature of the photoinduced structural metastability in amorphous selenium.

1.
M.
Kubota
 et al,
IEEE Trans. Broadcast.
42
,
251
(
1996
).
2.
K.
Tanioka
,
J.
Yamzaki
,
K.
Shidara
,
K. K.
Taketoshi
,
T.
Kawamura
,
T.
Hirai
, and
Y.
Takasaki
, in
Advances in Electronics and Electron Physics
, Vol.
74
, edited by
P. W.
Hawkes
and
B. L.
Morgan
(Academic Press, London,
1988
), p.
379
.
3.
A.
Reznik
,
B. J. M.
Lui
, and
J. A.
Rowlands
,
Technol. Cancer Res. Treat.
4
,
61
(
2005
).
4.
W.
Zhao
,
D.
Li
,
A.
Reznik
,
B. J. M.
Lui
,
D. C.
Hunt
,
Y.
Ohkawa
,
K.
Tanioka
, and
J. A.
Rowlands
,
Med. Phys.
32
,
2954
(
2005
).
5.
T.
Matsubara
 et al,
2005 IEEE Workshop on CCD and AIS
,
Nagano, Japan
, June
2005
(unpublished).
6.
A.
Reznik
B. J. M.
Lui
,
V.
Lyubin
,
M.
Klebanov
,
K.
Tanioka
,
M.
Kubota
,
K.
Miyakawa
,
Y.
Ohkawa
, and
J. A.
Rowlands
,
J. Non-Cryst. Solids
352
,
1595
(
2006
).
7.
B. T.
Kolomietz
and
V.
Lyubin
,
Mater. Res. Bull.
13
,
1343
(
1978
).
8.
K.
Tanaka
, in
Fundamental Physics of Amorphous Semiconductors
, edited by
F.
Yonezawa
(
Springer
,
Berlin
,
1981
), p.
104
.
9.
G.
Pfeifer
,
M. A.
Paessler
, and
S. C.
Agarwal
,
J. Non-Cryst. Solids
130
,
111
(
1991
).
10.
K.
Shimakawa
,
A.
Kolobov
, and
S. R.
Elliott
,
Adv. Phys.
44
,
475
(
1995
).
11.
H.
Fritzsche
, in
Insulating and Semiconducting Glasses
, edited by
P.
Boolchand
(
World Scientific
,
Singapore
,
2000
), p.
653
.
12.
V. L.
Averianov
,
A. V.
Kolobov
,
B. T.
Kolomiets
, and
V. M.
Lyubin
,
Phys. Status Solidi A
57
,
81
(
1980
).
13.
K.
Tanaka
and
A.
Odajima
,
Solid State Commun.
43
,
961
(
1982
).
14.
K.
Tanaka
and
A.
Odajima
,
J. Non-Cryst. Solids
46
,
259
(
1981
).
15.
K.
Tanaka
,
Jpn. J. Appl. Phys., Part 1
25
,
779
(
1986
).
16.
W.-D.
Park
and
K.
Tanioka
,
Jpn. J. Appl. Phys., Part 2
42
,
L209
(
2003
).
17.
K.
Tanaka
,
J. Appl. Phys.
65
,
2042
(
1989
).
18.
K.
Shimakawa
,
S.
Inami
, and
S. R.
Elliott
,
Phys. Rev. B
42
,
11857
(
1990
).
19.

Our preliminary results confirm the linear dependence between G and I.

20.
N.
Goto
,
E.
Maruyama
,
T.
Hirai
, and
T.
Fujito
,
Hitachi Hyoron
58
,
75
(
1976
).
21.
22.
V.
Palyok
,
I. A.
Szabo
,
D. L.
Beke
, and
A.
Kikineshi
,
Appl. Phys. A: Mater. Sci. Process.
74
,
683
(
2002
).
You do not currently have access to this content.