Abstract
The effect of film thickness on the optical and electrical properties of Cu-30 wt % GeO2-70 wt % thin cermet films prepared by electron-beam deposition at about 10−3 Pa and at a substrate temperature of 300 K is reported. The ultraviolet, visible and direct current (d.c.) conductivity results are analysed with the aim of determining the optical band gap,E opt, the width of the band tails,E e, and the d.c. thermal activation energy,E a. It was found that the optical energy gap increases with increasing thickness and that the absorption was due to indirect transitions ink-space. The general feature of the absorption edge remains similar for both unannealed and annealed films, but annealing has the effect of decreasingE opt. The d.c. conductivity results show thatE a decreases with increasing thickness. From a knowledge ofE opt andE a, a probable model of the electronic band structure in Cu-GeO2 thin films has been suggested.
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Al-Saie, A.M., Rahman, M.H. & Beynon, J. Film-thickness effects on the optical and electrical properties of Cu-GeO2 thin cermet films. J Mater Sci 28, 3675–3680 (1993). https://doi.org/10.1007/BF01159853
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DOI: https://doi.org/10.1007/BF01159853