An InAlAs-InGaAs OPFET with responsivity above 200 A/W at 1.3-mu m wavelength

The optoelectronic de and RF behavior of an InAlAs-InGaAs optically control led field-effect transistor based on a high electron mobility transistor la yer structure is investigated at 1.3-mu m wavelength light. The device is b ackside-illuminated to increase the responsivity, A transistor with 0.3-mu m gate length and an active area of 50 x 50 mu m(2) exhibits a responsivity of 235 A/W, at 11-mu W incident optical power. The photoconductive respons e is higher than for an metal-semiconductor-metal photodetector with the sa me InGaAs absorption layer thickness up to 10 GHz.