ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Admittance spectroscopy has been used to determine the value of the valence-band discontinuity in a p-type GaAs/Al0.3Ga0.7As multiple-quantum-well system. The structures were multiple quantum wells grown by molecular-beam epitaxy on semi-insulating GaAs substrates. Three Be-doped (p-type) GaAs wells, 30, 35, and 40 A(ring) wide, were used in these measurements. The barriers were undoped. Based on our measurements and a Fermi-level determination from an 8×8 envelope function approximation calculation of the valence electronic structure of the GaAs/AlGaAs system, the valence-band discontinuity, ΔEv, was found to be 0.165 eV. Using established relations, the band-gap difference in the GaAs/AlGaAs system ΔEg for xAl=0.3 was calculated to be 0.429 eV, which, together with the valence-band offset determined in this work, gives the ratio of the conduction–to–valence-band offsets as 60:40. These values are in excellent agreement with those determined by capacitance-voltage profiling, thus confirming the utility of the admittance spectroscopic technique for determining the band discontinuities in band-gap-engineered materials.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.356507
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