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In this work, we study the crystallization and electrical resistivity of the formed oxides in a Cu/SiO2/Si thin film after thermal oxidation by ex-situ annealing at different temperatures up to 1000 °C. Upon increasing the annealing temperature, from the X ray diffractogram the phase evolution Cu → Cu + Cu2O → Cu2O → Cu2O + CuO → CuO was detected. Pure Cu2O films are obtained at 200 °C, whereas uniform CuO films without structural surface defects such as terraces, kinks, porosity or cracks are obtained in the temperature range 300–550 °C. In both oxides, crystallization improves with annealing temperature. A resistivity phase diagram, which is obtained from the current–voltage response, is presented here. The resistivity was expected to increase linearly as a function of the annealing temperature due to evolution of oxides. However, anomalous decreases are observed at different temperatures ranges, this may be related to the improvement of the crystallization and crystallite size when the temperature increases.

A measuring system that separates the both waveforms of displacement and tunneling current using a scanning vibrating probe is described. In the measuring system, the displacement and tunneling current flow periodically in accordance with the perpendicular vibration of the probe. The external circuit current is measured by oscilloscope and is separated into both waveforms of the displacement and tunneling current by utilizing the phase difference of them. The waveform of the displacement current is also analyzed by assuming the presence of excessive surface charges above the sample. Consequently, we can determine the mean distance between the probe and sample, and the offset voltage which is built up by excessive surface charges and work function difference of the probe and sample.

The current-voltage (I-V) characteristic of Au/PI/(Rh-G2 + PI)/PI/Au (or Al) junctions was examined. An asymmetrical I-V characteristic with several steps was observed for Au/PI/PI:Rh-G2/PI/Al junctions, whereas a symmetric I-V characteristic with steps was obtained for Au/PI/PI:Rh-G2/PI/Au junctions. It was concluded that the presence of metal/organic interfacial states made a significant contribution to the I-V characteristics of these junctions.

Maxwell displacement current (MDC) measurement coupled with second harmonic generation (SHG) measurement was employed for the orientational order study of Langmuir films. 4-alkyl-4′-cyanobiphenyl ( n CB, n =5, 6, 7 and 8) Langmuir films were examined, and the orientational order parameters were determined. The difference in the generation between MDC and SHG was revealed, and was discussed based on the difference in the contribution of n CBs. It is shown that the measurement employed here is very helpful for the orientational study of Langmuir films.

Optical molecular switching in monolayers at the air-water interface due to the cis-trans photoisomerization of azobenzene derivative was first detected by the displacement current measurement. The displacement current was generated due to the trans-to-cis photo-isomerization of the azobenzene derivative by irradiation with UV light, whereas the displacement current was generated in the opposite direction due to the cis-to-trans photoisomerization by irradiation with visible light. The reversible displacement current generation was found to be sustained by alternative irradiation with UV light and visible light. Finally, the dipole moment transition with photoisomerization was estimated.

The reorganization upon compression of monolayers at the air-water interface could be detected with high sensitivity and high precision by using displacement current measurement. The displacement current was generated along with the monolayer-covering area due to a change in induced charges on an electrode suspended in air. Monolayers of fatty acids and of precursor films of polyimide (PAA(C 18 DMA) 2 ) formed on the water subphase were investigated without destroying the monolayers themselves in the entire range from the so-called gaseous phase to the solid phase at the same time. The vertical component of dipole moment of the constituent molecules of the monolayers was also determined along with the monolayer-covering area.

The reversible displacement current was generated from a single monolayer of l -α-dioleoyllecithin (DOL) formed on the water surface by regulated application of repeated decrease and increase of the DOL monolayer covering-area with the aid of a movable barrier. The behavior of the surface pressure—area isotherm of the DOL monolayer was reversible along with the increase and decrease of the monolayer-covering area. In addition, the reversible change in the surface micro-structure of a DOL monolayer system was visualized at various two-dimensional molecular densities by using a new replica technique coupled with transmission electron microscopy. We concluded that the displacement current measurement and the replica technique are useful for a better understanding of the relationship between the function and structural change of monolayers.

We developed a new current-measuring technique to replace the conventional surface potential method. In this technique, two electrodes parallel to the water surface are used. One electrode (electrode 2) is placed in the water while the other (electrode 1) is suspended in the air. Both electrodes are grounded. Investigation of the physical properties of fatty acid monolayers at the air-water interface was carried out by using the technique, and the vertical component μz of the dipole moment of the acid molecules was determined. From the investigation, we found that the behaviour of molecules at the edge of the trough plays a very important role in the current measurement. Finally, it was concluded that the dipole moment of the acids determined by the present current-measuring technique, when electrode 1 was electrically shielded, is in good agreement with that determined by the conventional surface potential method.