Si-delta doping and spacer thickness effects on the electronic properties in Si-delta-doped AlGaAs/GaAs HEMT structures

In this work, we investigate the effect of the delta-Si doping on the barrier and the spacer thickness on the electronic properties of AlGaAs/GaAs HEMTs structures grown by molecular beam epitaxy on (100) oriented GaAs substrates. Photoluminescence measurements as function of the temperature are used to determine the relaxation processes of the electron and the hole in the channel. The photoluminescence characterizations of Si-delta-doped AlGaAs/GaAs HEMTs structures have been studied in the 10-300 K temperature range. Low temperature PL spectra show the optical transition (Ee-h) that occurs between the fundamental states of electrons to holes in the GaAs channel. Increase of the Si-delta-doping density and decrease of the spacer width improve the two-dimensional electron gas confinement and decrease defects densities in the canal. The band structure of Si-delta-doped AlGaAs/GaAs HEMTs structures at T = 10 K has been studied theoretically using the finite differences method to self-consistently and simultaneously solve Schrodinger and Poisson equations written within the Hartree approximation. (C) 2012 Elsevier Ltd. All rights reserved.