Space- and time-resolved photoluminescence of In-alloyed GaAs using photoluminescence excitation correlation spectroscopy

Photoluminescence excitation correlation spectroscopy is used to space and time resolve photoluminescence (PL) intensity variations in the region of isolated dislocations in as-grown In-alloyed GaAs. Spatially resolved PL maps show an annulus of high intensity with an inner and outer dark background surrounding a dislocation. Typical inner and outer diameters of the annuli are about 200 and 400 µm, respectively, which is smaller than the average dislocation separation in In-alloyed GaAs. Temporal resolution of the PL measures the carrier lifetime in the bright and dark regions. These measurements show that the lifetime variation accounts for the PL intensity variation. The variation of the lifetime with temperature indicates that the defects governing the lifetimes in the bright and dark regions are different. Moreover, both defects are deep and neither defect is EL2.