AC electrical conductivity of electron beam evaporated Cu-GeO2 thin cermet films |
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Authors: | M H Rahman A M Al-Saie J Beynon |
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Affiliation: | (1) International Development Consultants, 25 Condie Street, Nepean, Ontario, Canada, K2G 5M3;(2) Department of Physics, University of Bahrain, P.O.Box 32038, Bahrain, Arabian Gulf;(3) Department of Physics, Brunel University, Uxbridge, Middlesex, UB8 3PH, UK |
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Abstract: | AC electrical properties of 410 nm think 30 at.wt% Cu-70 at.wt% GeO2 thin films are reported for the frequency range 104 to 106 Hz and temperature range 150 to 425 K. The loss tangent (tan ) and the dielectric loss (/0) are found to show striking minima around a cut-off frequency 105 Hz. In the lower frequency range (105 Hz), 1()
s
T
n
is obeyed with s (0 to 0.51) increasing as a function of temperature and n (0.10 to 0.14) showing a very weak temperature dependence. In the higher frequency region (105 Hz), 1() and /0 increase sharply leading to the quadratic behavior of 1() with s equal to 2. These processes are discussed by analyzing an equivalent circuit which shows that at lower frequencies, the effects of series resistance in leads and contacts can be neglected, while at higher frequencies such effect give rise to spurious 2 dependance for the conductance. A weakly activated AC conductivity and a frequency exponent s that increases with increasing temperature suggest that the low frequency behavior originates from carrier migration by tunneling process. |
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