Publications Details
Intrinsic and interfacial recombination in OMVPE- and MBE-prepared GaAs/Al{sub x}Ga{sub 1-x}As heterostructures
We have studied intrinsic free-carrier recombination in a variety of GaAs structures, including: OMVPE- and MBE-prepared GaAs/Al{sub x}Ga{sub 1-x}As double heterostructures, Na{sub 2}S passivated GaAs structures and bare GaAs structures. We find OMVPE prepared structures are superior to all of these other structures with 300 K lifetimes of {approximately} 2.5 {mu}s and negligible nonradiative interface and bulkrecombination, and thus are truly surface-free (S < 40 cm/s). Moreover, we observe systematic trends in optical properties versus growth conditions. Lastly, we find that the presence of free-exciton recombination in the low-temperature photoluminescence spectra is a necessary but not sufficient condition for optimal optical properties (i.e. long minority-carrier lifetimes).