BAND-OFFSET DETERMINATION IN PARABOLIC AND TRIANGULAR QUANTUM-WELLS OF GAAS/ALGAAS AND GAINAS/ALINAS

The band offset parameter. Q(c)=DELTAE(c)/DELTAE(g) for both GaAs/A]GaAs, and GaInAs/AlInAs (lattice matched to InP) was extracted from electron beam electroreflectance interband transition energies obtained from molecular-beam epitaxially grown parabolically and triangularly shaped quantum wells (QWs). Most of the QWs were grown using continuous analog grading. Additionally, for comparison, two 500 angstrom GaAs/AlGaAs, superlattice (digitally) graded, parabolic QWs, with bilayer thicknesses of 25 and 12.5 angstrom, were also evaluated. Q(c) values obtained were 0.661+/-0.015 and 0.650+/-0.005 for GaAs/AlGaAs and GaInAs/AlInAs, respectively. Measurements also revealed that Q(c) was both temperature and concentration independent.