Photoluminescent characterization of diffusion-doped III-V photovoltaics: insights into annealed melt grown n-GaAs

We report steady-state and time-resolved photoluminescent (PL, TRPL) characterization of melt-grown n-GaAs and diffusion doped p+/n GaAs photovoltaic cells. Samples are processed via annealing in an arsenic poor ambient to mitigate arsenic-rich defect populations. p+/n junctions are formed via diffusion doping. We attempt to characterize and identify defects that limit photovoltaic efficiency in these cells. Time-resolved PL is used to predict bulk lifetime of GaAs cells. Low temperature PL of samples are compared, and defects are identified. Optical absorption and charge transport calculations are reported to demonstrate the efficiency potential of high-quality diffusion doped cells.