Photoluminescence spectroscopic and electron beam-induced current techniques were used to characterize misfit dislocations in epilayers after H plasma treatment at temperatures of between 200 and 500C. Low-temperature electron-beam-induced current measurements showed that most (90%) of the shallow levels which were associated with misfit dislocations were not passivated, whereas deeper mid-gap levels were readily passivated. The dislocation-related luminescence features (D bands) were all reduced in intensity by H treatment. At 300C, D1 was preferentially passivated and could no longer be observed, whereas the other D bands (although reduced in intensity) could still be observed. De-passivation experiments showed that, following post-hydrogenation annealing at 600C, the deep levels were passivated (according to electron beam-induced current data) and the D bands were regenerated.

V.Higgs, M.Kittler: Applied Physics Letters, 1994, 65[22], 2804-6