Abstract :
Photo-induced-current transient spectroscopy and capacitance–voltage measurements on nominally undoped p-CdTe
single crystals grown by a Bridgman method have been carried out to investigate the hydrogenation and the annealing effects
on the deep levels and on acceptor neutralization. The five hole-traps of the as-grown p-CdTe and their activation energies
were Evq0.21 H1., Evq0.39 H2., Evq0.43 H3., Evq0.65 eV H4., and Evq0.75 H5.. After the p-CdTe was
hydrogenated and annealed, H4and H5related to Cd vacancies disappeared, and the intensity of H3 related to the native
defects decreased by a factor of 2. H4 and H5 traps were passivated by the hydrogen atoms. The H3 defect level is
considered to be due to complexes of Cd vacancies and impurities, and the H2 signal is associated with complexes of
shallow impurities. The results of the PICTS measurements showed that hydrogen atoms easily neutralize the Cd vacancies
and that the hydrogen atoms are easily separated from the impurities by the thermal energy. These results indicate that the
electrical properties of the undoped p-CdTe single crystals are improved by hydrogenation and annealing and that
hydrogenated and annealed CdTe crystals hold promise as useful substrates for the growth of HgxCd1xTe. q1999 Elsevier
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