The 5d transition-metal impurity, osmium, has been incorporated during the growth of n-type GaAs epitaxial layers using low-pressure metal-organic chemical-vapor deposition to characterize defect states associated with this heavy and, therefore, thermally stable dopant impurity.... (Read more)

Deep levels due to 5d transition metal, osmium (Os), in n-type GaAs epitaxial layers grown by metal-organic vapour-phase epitaxy are investigated using deep level transient spectroscopy (DLTS). Two clear and prominent peaks are observed in majority carrier (electron) emission spectra in GaAs:Os samples in addition to a weaker, broad feature at higher temperatures, which are absent in the Os-free, reference samples. The well-resolved, prominent peaks are attributed to deep levels associated with Os impurity having activation energies E_c−0.28 eV and E_c−0.41 eV at a junction electric field of not, vert, similar1.4×10⁵ V/cm. Both of these peaks are found to be field dependent. Detailed data on emission rate signatures, apparent electron capture cross-sections and defect concentrations are reported for these levels. No Os-related deep level peaks could be clearly delineated in minority-carrier injection DLTS, at this stage, although some evidence is found for a low-energy deep level band. (Read more)