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Changes in the photoconductivity of sputtered films of cadmium sulphide resulting from oxygen chemisorption
The effect which O 2 has on the photocurrent flowing parallel to the surface in sputtered thin films of cadmium sulphide is investigated. The photocurrent was observed to be inversely related to the partial pressure of O 2 in a flowing N 2 environment. By using Wolkenstein's theory of “weak” an...
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Published in: | Surface science 1973-12, Vol.40 (3), p.555-570 |
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Main Authors: | , |
Format: | Article |
Language: | English |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | The effect which O
2 has on the photocurrent flowing parallel to the surface in sputtered thin films of cadmium sulphide is investigated. The photocurrent was observed to be inversely related to the partial pressure of O
2 in a flowing N
2 environment. By using Wolkenstein's theory of “weak” and “strong” chemisorption, an expression describing the rate at which gas introduced surface states become filled is derived,
dN′
s
dt
= aN
∗
s
exp( − bN′
s
) − c × ×
exp(bN′
s
)
, where
N′
s is the density of surface states introduced by the gas being detected. Relating
N′
s(
t) to the photocurrent
I
p(
t) allows comparison of experimental and theoretical curves. The chemisorption time constant τ
c is found to be inversely related to gas partial pressure, light intensity, and temperature. |
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ISSN: | 0039-6028 1879-2758 |
DOI: | 10.1016/0039-6028(73)90144-1 |