HEMTにおける光応答特性

We investigated the optical response of high electron mobility transistors (HEMTs). We employed a 0.1μm-gate-length InAlAs/InGaAs/InP-based HEMT as a test sample. To clarify the feasibility of the device in fiber-optic communication systems, the wavelength of all optical lights were set to 1.55μm. The dependence of the device on input light intensity was measured togerther with its optical pulse response. For the latter, we employed the electro-optic sampling techniques. We observed the photocurrent of 0.125A/W from the DC measurements, on the other hand, its bandwidth was limited to several GHz. We report these measured results and then discuss the carrier transport mechanism which describes them. Finally, some applications which utilize the merits of optically illuminated HEMTs are described.