Deep-level transient spectroscopy was used to measure the activation energies of deep levels in n-type heterostructures which had been grown by means of solid-source molecular beam epitaxy. Four deep levels were observed at energies ranging from 0.231 to 0.405eV below the conduction band. The largest deep-level concentration was found for the deepest level, and was equal to about 2 x 1015/cm3. Although a large amount (1 to 2at%) of non-substitutional C was present in the alloy layers, no deep levels were observed at any energy levels that had apparently been previously attributed to interstitial C.

B.L.Stein, E.T.Yu, E.T.Croke, A.T.Hunter, T.Laursen, J.W.Mayer, C.C.Ahn: Applied Physics Letters, 1998, 73[5], 647-9