Electron diffusivity in p-InGaAs determined from the pulse response of InP/InGaAs uni-traveling-carrier photodiodes

The minority electron diffusivity of p-In0.53Ga0.47As measured through the photoresponse of uni-traveling-carrier photodiodes is reported. An electro-optic sampling technique was used to determine the parameter with good accuracy. The obtained diffusivities are 260, 130, and 86 cm2/s at the acceptor doping levels of 2.5×1017, 1.0×1018, and 2.5×1018 cm−3, respectively. These values are contrary to those obtained from the theoretical analysis, which predicts a 50% mobility reduction by coupled polar-phonon plasmon scattering in the doping range below mid-1018 cm−3.