Photoluminescence spectroscopy of Cadmium Telluride deep defects

Deep defect states of Cadmium Telluride deposited via close space sublimation and magnetron sputtering are evaluated via steady state and time resolved photoluminescence. Intensity dependent photoluminescence measurements for as-grown and cadmium chloride treated samples reveal the recombination mechanism associated with each transition. The as-grown sputtered film photoluminescence is weak with broad features while the close space sublimation film photoluminescence is comparatively bright and dominated by a deep donor acceptor pair recombination. Unlike excitonic or free-to-bound transitions, donor acceptor pair recombination exhibits a distance dependence that determines the distribution of transition energies and recombination rates. We measure the PL lifetime with respect to energy as a direct observation of the increasing donor acceptor pair recombination rate with decreasing donor-acceptor separation.