The properties of n-type epilayers which had been grown onto (100) GaAs substrates by means of molecular beam epitaxy were reviewed with regard to photoluminescence, secondary ion mass spectroscopic and deep-level transient spectroscopic data. Great emphasis was placed on the effect of various dopants, and the role played by deviations from stoichiometry, upon doped epitaxial layers. Considerable attention was paid to the characterization and identification of deep-lying defect states; both the native ones and those introduced by dopants. In the case of ZnSe, the deep-level transient spectroscopic results revealed why Cl was superior to Ga as an effective n-type dopant. This was because Cl, unlike Ga, did not itself introduce any detectable deep defects into the ZnSe lattice.

G.Karczewski, T.Wojtowicz: Acta Physica Polonica A, 1996, 90[4], 635-44