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Temperature dependence of electron tunneling

University of British Columbia

The variation with temperature of electron tunneling through thin insulating films of A1₂0₃ between aluminum film electrodes was studied at liquid helium temperatures (1.18°K to 4.2°K) and liquid oxygen temperatures (65°K to 90°K). Samples were prepared in a vacuum evaporating system using the method developed by Fisher and Giaever (1961). The aluminum oxide films were grown in air at room temperature. Resistance was measured as a function of voltage by means of a d.c. Wheatstone bridge for sample currents in the region of 10⁻⁷ amps. Conduction due to electron tunneling was indicated by the non-ohmic voltage dependence of resistance and by the fact that the resistance increased with a decrease in temperature. The voltage dependence of the tunneling resistance was found to be in good agreement with the theory as derived by Simmons (1963), and was parabolic for low voltages. Reliable and reproducible data for the temperature dependence of resistance were difficult to obtain because of instabilities in the samples and a general increase in resistance due to aging. Comparison of the observed temperature dependence with the theory of Simmons (1964) showed the variation to be approximately twice as great as predicted.

Text

2011-09-14

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http://hdl.handle.net/2429/37329

Physics

University of British Columbia

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