Measurements of carrier lifetimes of GaAs/AlGaAs core-shell nanowires on Si(111) substrates
Abstract
Core-shell GaAs/AlxGa1−xAs nanowires with different diameters grown on Si(111) were investigated using room temperature time-resolved photoluminescence spectroscopy. The carrier lifetime for both the GaAs core and AlGaAs shell were measured. Both shell and core exhibits a double decay rate and a faster decay rate is observed for the AlGaAs shell. The initial fast decay in the AlGaAs is attributed to carrier transfer from the shell to the core while the slower decay is attributed to recombination of carriers within the shell. The origin of the double decay rate for the core still needs further investigation. However, one mechanism involved is the recombination of carriers within the core. This is the first reported measurement of the carrier lifetime of the shell material for GaAs/AlxGa1−xAs core-shell nanowires.