Conduction and valence band offsets in GaAlAs/GaAs/GaAlAs quantum wells from photo-luminescence and deep level transient spectroscopy under hydrostatic pressure

It is shown that deep level transient spectroscopy at low temperatures and under hydrostatic pressure on MBE grown GaAlAs/GaAs/GaAlAs quantum wells using Au Schottky barrier diodes combined with photo-luminescence (PL) measurements provides a powerful tool for determining the conduction and valence band offsets if the well is considered as a ‘giant’ trap having characteristics very different from a normal trap. The conduction and valence band offsets have been determined to be 72 and 28% of GaAs/GaAlAs forbidden energy band gap difference as determined by PL measurements on samples with varying well thickness for the same GaAlAs compositions of the binding layers.