Deep-level transient spectroscopy was used to characterize defects in n-type samples which had been grown by using reactive molecular-beam epitaxy. Five deep-level defects were observed, with activation energies of 0.234eV (E1), 0.578eV (E2), 0.657eV (E3) 0.961eV (E4) and 0.240eV (E5). The E1, E2 and E3 levels corresponded to deep levels which had been previously reported for n-type material which had been grown by using both hydride vapor-phase epitaxy and metal-organic chemical vapor deposition. The E4 and E5 levels did not correspond to any previously reported defect levels, and were characterized for the first time here.

C.D.Wang, L.S.Yu, S.S.Lau, E.T.Yu, W.Kim, A.E.Botchkarev, H.Morkoç: Applied Physics Letters, 1998, 72[10], 1211-3