Takehiro Oishi

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A solar-pumped 100 W class laser that features high efficiency and low cost owing to the use of a Fresnel lens and a chromium codoped neodymium YAG ceramic laser medium was developed. A laser output of about 80 W was achieved with combination of a 4 m(2) Fresnel lens and a pumping cavity as a secondary power concentrator. This output corresponds to 4.3% of(More)
A Nonlinear Circuit Model (NCM) combined with device/physical parameters was developed by using hyperbolic tangent (tanh) function and applied to GaN high electron mobility transistors (HEMTs). The equations for the NCM were constructed to reproduce the results of a device physical simulation. Model parameters are similar with the parameters used in the(More)
This is the first report of catalytic vapor deposition (Cat-CVD) passivated AlGaN/GaN HEMT. We have found out that the Cat-CVD passivation film with NH3 treatment greatly enhances the reliability of the AlGaN/GaN HEMT. It is rationalized, through the low frequency capacitance-voltage measurement, that the NH3 treatment in the Cat-CVD reactor before the SiN(More)
The two-dimensional effect in the reverse gate leakage current of GaN HEMTs is studied by using the TCAD simulation. At the high voltage region, the extension of the potential from the gate to the drain latterly is important role for the reverse gate leakage current characteristics. On the other hands, the electrons flow vertically from the gate electrode(More)
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