Katsushi Akita

Learn More
The authors report their latest results on II-VI intersubband all-optical switches in which the 10 dB absorption saturation energy is lowered to ~2.0-2.2 pJ for 1.55-1.58 mum by decreasing the thickness of the active layer and increasing the refractive index difference between the core layer and the cladding layers in waveguides. Such low saturation(More)
AlGaN-channel high-electron mobility transistors (HEMTs) on an AlN substrate have been fabricated for the first time. A maximum saturation current of 0.13A/mm at V GS =2V and a maximum transconductance of 25mS/mm were obtained. DC characteristics of AlGaN-channel HEMT and GaN-channel HEMT were comparatively examined at temperatures ranging from RT to 300ºC.(More)
SUMMARY This paper describes high-temperature electron transport properties of AIGaN-channel HEMT fabricated on a free-standing A1N substrate, estimated at temperatures between 25 and 300°C. The AIGaN-channel HEMT exhibited significantly reduced temperature dependence in DC and RF device characteristics, as compared to those for the conventional A1GaN/GaN(More)
We demonstrate an AlN/AlGaN high-electron-mobility transistor (HEMT) fabricated on a free-standing AlN substrate. A metal stack, composed of Zr/Al/Mo/Au, was found to show low contact resistivity for source and drain ohmic contacts. The fabricated AlN/AlGaN HEMT exhibited a maximum drain current of 38 mA/mm with a threshold voltage of-3.4 V. Negligible(More)
  • 1