A study on photoreflectance characteristics of interface effect in Si delta-doped Al0.24Ga0.76As/In0.2Ga0.8As/GaAs pseudomorphic high electron mobility transistor structures

We study the photoreflectance (PR) characteristics of interface effect in Si delta-doped Al0.24Ga0.76As/In0.2Ga0.8As/GaAs pseudomorphic high electron mobility transistor (pHEMT) structure. We observed weak 11H transition from the PR spectrum of pHEMT, and the room- and low-temperature PR spectra exhibited Franze–Keldysh oscillations at energies above the GaAs band gap. From the period of these oscillations, the electric feild at the Al0.24Ga0.76As/In0.2Ga0.8As/GaAs interface was determined and behaviour decreasing with temperature was observed.