Effects of D-Doping on Characteristics of AlAs/GaAs Barriers Grown by Mba at 400 ??C


Electerical Engineering, Tarbiat Modarres University


Effects of d-doping on barriers effective heights and series resistance of highly doped n-type GaAs/AIAs/GaAs/AlAs/GaAs heterostructures, grown by molecular beam epitaxy (MBE) at 400?°C, have been studied. As it was expected, inclusion of an n+ d-doped layer at each hetero-interface has reduced the barriers heights and series resistance of the structure significantly, while p+ d-doped layers have enhanced the barriers heights and the sructure series resistance. Using the Arrhenius plots, values of the effective heights for normal, n+ d-doped and p+ d-doped barriers were estimated to be 50,20 and 170 meV, respectively. The approximated values of the specific resistances, Rc, at room temperature and around zero volt bias, for the respected devices are 8x10-3 W-cm2, 4x10-4 W-cm2 and 6x10-2 W-cm2, respectively.