Katsunori Hatanaka

71.2: Fabrication and Characterization of Surface Conduction Electron Emitters

We have developed a surface conduction electron emitter (SCE) for next-generation flat displays. PdO thin films (approximately 10 nm) produced by the ink-jet process were used for forming the surface conduction electron emitter. The films were electroformed and activated while a certain voltage was applied, and an electron emitter with good characteristics was obtained. A current density of approximately 30 mA/cm2 was attained when an anode voltage of 10 kV was applied. We confirmed operation for 60,000 hours by an acceleration test at a current density of 3 mA/cm2. This current density is required for “good brightness” on the surface conduction electron emitter display (SED).

Switching and memory phenomena in Langmuir–Blodgett films with scanning tunneling microscope

The current‐voltage characteristic has been measured for a probe/Langmuir–Blodgett (LB) film/metal structure with the scanning tunneling microscope (STM). The rapid increase of current and substantial increase in conductance have been found when a critical positive voltage was applied to the probe. A bright spot in the STM image has been observed at the position where the increase in the conductance occurred. The changes in the STM images are attributed to the change in the conductance of LB films themselves rather than the surface topography, and may be associated with the switching phenomena in LB films.

Barrier-height imaging of fatty acid Langmuir-Blodgett films

Abstract Behenic acid Langmuir-Blodgett films on graphite have been investigated by STM using the AC gap-modulation technique. Two significant differences were observed as compared to conventional topographic images. (1) The periodic contrast variation, which is superimposed on the structure of the behenic acid molecules in the lamellar arrangement, is greatly enhanced. This period corresponds to the width of 6 molecules. (2) The carboxyl groups appear featureless and cannot be distinguished, whereas in the topographic images they are the brightest signal and are clearly distinguished. The periodic variation of enhanced contrast corresponds to that of the positional relation between the adsorbed molecules and the underlying substrate. This means that the additional information of the interaction between the adsorbed molecules and the substrate can be obtained by the gap-modulation mode in STM.

Parallel arrangement of fatty acid molecules in films deposited at a lower surface pressure

Abstract It is widely believed that Langmuir-Blodgett films deposited at a lower surface pressure, i.e. in a rather expanded phase, have a disordered structure. Using a scanning tunneling microscope, however, we have found, unexpectedly, ordered structures in fatty acid films deposited at lower surface pressures onto single-crystal substrates such as highly oriented pyrolytic graphite and molybdenum disulfide, where the molecules adhere with their long axes parallel to the substrate surface.