Extrinsic Photoluminescence in Unintentionally and Magnesium Doped GaInAs/GaAs Strained Quantum Wells
Low temperature photoluminescence spectra of various InxGa1-xAs/GaAs strained quantum wells and superlattices have been analyzed to study the contribution of residual and magnesium acceptors to the photoluminescence emissions. Sharp and intense structures due to free exciton recombinations dominate the spectra of undoped samples. These structures broaden, and weaker emissions on their low energy side become more prominent when intentional p-type doping is larger than 1016 cm-3. The broadening of the excitonic structure is interpreted as being due to additional emission from excitons bound either to neutral acceptors in the wells or to impurities or defects at the well-barrier interfaces. The small structures are due to recombinations between electrons and acceptors confined in the wells. The binding energy of the acceptors deduced from the spectra is compared to that calculated taking into account the strain induced valence band splitting and the large heavy hole anistropy, together with the binding energy enhancement due to confinement.
KeywordsExcitation Power Heavy Hole Free Exciton Hole Band Strained Layer
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