Photoluminescent properties of GaAs–GaAlAs, GaAs–oxide, and GaAs–ZnS heterojunctions

The band edge photoluminescence of GaAs structures has been studied as a function of greater than band edge excitation energies. For p–p–n, GaAlAs–GaAs–GaAs, and p–n GaAs solar cell structures, it was found that the photoluminescent response curves were similar to the short circuit current response curves. A computer simulation program was developed to extract information about minority carrier diffusion lengths and surface and interface method for both qualitative and quantitative evaluation of processing and fabrication steps on GaAs based structures. For example, it was found that ZnS–GaAs heterostructures showed an increase in photoluminescent response with annealing time at 500°, and that anodized GaAs showed a higher response than ’’bare’’ GaAs which then decreased after a 450° anneal.