The electrostatic potential profile across AlGaAs/AlAs/GaAs heterostructures containing 1-μm -thick n -doped (or p -doped) AlGaAs layers is measured using off-axis electron holography. Simulations of the potential profiles assuming no unintentional impurities in the undoped regions of the samples show small discrepancies with experiment. Revised simulations reproduce the measurements accurately, when a p -layer with an 8.4× 1011 cm-2 acceptor density is included at the buffer/substrate interface to simulate the presence of unintentional carbon impurities.
ASJC Scopus subject areas
- Physics and Astronomy(all)