OPTICAL AND ELECTRICAL-PROPERTIES OF YTTERBIUM-DOPED GAAS GROWN BY METALORGANIC CHEMICAL VAPOR-DEPOSITION

Optical and electrical properties of ytterbium-doped GaAs are investigated. The samples are grown by low-pressure metalorganic chemical vapor deposition using tris-cyclopentadienyl ytterbium as the ytterbium doping source. Yb concentrations in the GaAs epitaxial layers, which were measured by secondary ion mass spectroscopy, are well controlled by the source temperature up to 1.4×1019 cm-3, but GaAs:Yb samples do not show Yb intra-4f-shell photoluminescence. Hall effect and deep-level transient spectroscopy measurements reveal that the Yb doping forms deep electron traps or acceptor levels. The depth of such levels is likely to be responsible for the absence of Yb 4f photoluminescence in GaAs:Yb, in contrast to the strong Yb luminescence observed in InP:Yb.