Minority carrier lifetime analysis of bulk and interfaces on MOVPE grown III-V Low bandgap solar cell materials

We report on time- and spatially resolved photoluminescence measurements using InP/GaInAs/InP double hetero structures (DH-structures) to determine the crucial minority carrier lifetime for the Ga_0.47In_0.53As to InP interface which is basic for optoelectronic and photovoltaic applications. Different preparation routes, such as group III- and group V-rich variations are presented with respect to their lifetimes, interface recombination velocity and lateral interface homogeneity. From a series of different thick DH-structures at a fixed excitation density for chosen interface preparation routes the bulk lifetime and interface recombination velocity are extracted. Overall low interface recombination velocities occur, while one group III-rich preparation route results in comparable lifetimes at all excitation densities to the group V-rich preparation but with a much higher lateral homogeneity.