Previous descriptions of scanned probe oxidation kinetics involved implicit assumptions that one-dimensional, steady-state models apply for arbitrary values of applied voltage and pulse duration. These assumptions have led to inconsistent interpretations regarding the fundamental processes that contribute to control of oxide growth rate. We propose a model that includes a temporal crossover of the system from transient to steady-state growth and a spatial crossover from predominantly vertical to coupled lateral growth. The model provides an excellent fit of available experimental data.

The ZnGa204 phosphor has been investigated for its application to vacuum fluorescent displays (VFDs) utilizing lowvoltage cathodoluminescence. It is expected that this oxide phosphor does not cause damage to filaments in VFD's, while it is a serious problem for conventional sulfide phosphors. This phosphor shows blue luminescence with a spectral peak at 470 nm and a chromaticity at X = 0.170 and Y = 0.130. A luminous efficiency of 0.7 lm/W has been obtalned, when the VFD with this phosphor is operated at 30 V dc. The results of high-temperature operating life test have proven the excellent stability of VFDs utilizing this phosphor.Presently, sulfide phosphors are extensively used for vacuum fluorescent displays (VFDs). However, as previously discussed by the authors (1), sulfide phosphors emit sulfide gases and decompose to scatter phosphor material during electron excitation. This causes not only the decrease of luminous efficiency of the phosphors but also the deterioration of cathode filament, which are serious problems in multicolor VFDs.An attempt has been made to study the ZnGa204 powder phosphor to be used as the alternative of blue cathodoluminescent phosphor of ZnS:C1 phosphor. The ZnGa204 phosphor is a compound oxide of ZnO and Ga20~, crystallizing in the spinel structure, and its optical bandgap is about 4.4 eV. ZnGa204 shows emission from green to red when it is doped with Cr and Mn, and also shows blue emission even without being doped with impurity. It is well known that the phosphor is excited by electronbeams followed by energy transfer to the luminescent center to emit light. Therefore, the essential requirements for low-voltage cathodoluminescent (LCL) phosphors are low resistance and low threshold voltage, as well as excellent crystallinity. In view of these requirements, the ZnGa204 phosphor, which is inherently low in conductivity, was added with conductive materials. This paper mainly discusses the luminous characteristics of the phosphor which was applied to the VFD. REFERENCE

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Scanned probe microscope (SPM) oxidation with voltage modulation leads to a significant enhancement of the oxide growth rate, improvement of the aspect ratio of oxide features, and control of the structural and electrical properties of the SPM oxide. Variation of the voltage-pulse parameters confirms that the oxide dimensions can be controlled sensitively over a wide range of pulse parameters and that voltage modulation overcomes the self-limiting character of SPM oxidation by reducing the buildup of space charge within the oxide during growth. The enhancement can be used to increase the writing speed or lower the voltage, both beneficial for practical nanoelectronics fabrication.

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