Electron and Proton Radiation Effects on Band Structure and Carrier Dynamics in MBE and MOCVD Grown III-V Test Structures

As part of a continuing study on radiation effects in photovoltaic materials, we exposed a series of AlGaAs /GaAs double heterostructures grown by molecular beam epitaxy and metalorganic chemical vapor deposition to electron and proton radiation. The active regions of the test articles were doped either unintentionally, p-type or n-type. Steady state and time resolved photoluminescence spectroscopy were used to characterize changes to the band structure and carrier dynamics. The effect of electron radiation on low temperature photoluminescence spectra and on room temperature carrier lifetime varied with dopant type and density. Steady-state photoluminescence reveals distinct effects from electron and proton exposures-