Leakage and emission characteristics of condenser cathodes with thin layer of Al2O3

The paper gives the leakage and emission characteristics of sandwich cathodes of the type Al-Al₂O₃-Au prepared on polycrystalline Al and on a layer of Al deposited in vacuum with a layer of Al₂O₃ 100–500 Å thick. The samples with a monotonous leakage characteristic have an exponential emission characteristic and the samples with anomalous leakage characteristic showing a maximum have an emission characteristic beginning at anomally small voltages on the sample and in the energy spectrum they exhibit excess energy. The relationship between these two types and the method of preparing the layers is given. Measurements are described which bear witness to the slow processes taking place in the cathode and the paper gives hypotheses on the mechanism of emission from such cathodes.Thanks are due to I. Emmer who prepared a number of samples and performed several measurements (Figs. 3, 10) for paper 14] which the present author has used here.