Photoemissive Determination of Barrier Shape in Tunnel Junctions

Tunnel junctions have been characterized in terms of three parameters, the barrier heights φ_1, and φ_2, and the width S, which generally are determined by a fit of experimental current-voltage characteristic curves with theory. In metal-semiconductor systems barrier heights have been determined independently of other parameters from measurement of the spectral dependence of photoresponse. We wish to report the first results of the application of this technique to the measurement of the barrier heights in Al-Al_2O_3-A1 and Al-A1_20_3—Au tunnel junctions where the Al_2O_3 thickness is in the range of 20 to 40 Å