A study of impurity-free vacancy disordering in GaAs-AlGaAs forimproved modeling

摘要

A study of the parameters of the process of impurity-free vacancyndisordering (IFVD) of GaAs-AlGaAs quantum-well structures is presented.nThe study includes photoluminescence excitation measurements which shownthat the as-grown barrier/well interface is better fitted by annexponential profile than a square profile. This has a significant effectnon the intermixed diffusion profiles. Also, deep level transientnspectroscopy measurements have been conducted on samples that werenprocessed using IFVD. The measurements show an elevated concentration ofnthe trap EL2 in the processed samples, which is known to be related tonAs antisites. The concentration of such defects agrees with thenconcentration calculated for IFVD to within an order of magnitude,nsuggesting a correlation between the point defects required for IFVD andnEL2. Finally, temporally and spatially resolved photoluminescencenmeasurements were conducted on processed samples which indicate a factornof 3 reduction in the photogenerated carrier life time after undergoingnIFVD. A spatial resolution better than 3 Μm has been observed