InAlAs/InAs/InGaAs pseudomorphic high electron mobility transistors exhibiting ultra-fast optical response

High electron mobility transistors with a pseudomorphically strained InAs channel (InAs-PHEMTs) have superior electron-transport properties and high electron density, which are due to a large conduction-band discontinuity. In this work, we demonstrate that InAs-PHEMTs have an additional property: they exhibit an ultra-fast optical response with a timeconstant of 3.5 x10 ^-11 s. By irradiating the optical signal onto the InAs-PHEMTs, hole-electron pairs are created in the channel layer. Holes accumulated in the source region of the channel layer recombine immediately with 2DEG due to an Auger recombination mechanism. Holes generated in the region outside the gate also recombine immediately with the 2DEG due to the Auger recombination mechanism before they drift or diffuse toward the gate region. This is why the optical response time of an InAs-PHEMT is extremely small and it is restricted by the time for holes to transit across the gate region. A circuit incorporating an InAs-PHEMT as a transistor and an InAlAs/InAs/InGaAs MSM photodiode that has the same structure as an InAs-PHEMT as an optical detector has the potential to be applied as an ultra-fast receiver optoelectronic integrated circuit.