Growth and characterization of DyP/GaAs and DyAs/GaAs-based heterostructures and superlattices

Abstract Details of the structural and electrical properties of epitaxial DyP/GaAs and DyAs/GaAs is reported. DyP is lattice matched to GaAs, with a room temperature mismatch of less than 0.01%. DyAs, on the other hand, has a mismatch of nearly 2.4%. Both DyP and DyAs have been grown by solid source MBE using custom designed group V thermal cracker cells and group III high-temperature effusion cells. High-quality DyP and DyAs epilayers, as determined by XRD, TEM, and AFM analysis, were obtained for growth temperatures ranging from 500°C to 600°C with growth rates between 0.5 and 0.7 μm/h. The DyP epilayers are n-type with measured electron concentrations of the order of 3×10 20 to 4×10 20  cm −3 , with room temperature mobilities of 250–300 cm 2 /V s, and with a barrier height of 0.75 eV to GaAs. The DyAs epilayers are also n-type with concentration of 1×10 21 to 2×10 21  cm −3 , with mobilities between 25 and 40 cm 2 /V s. DyP is stable in air with no apparent oxidation taking place, even after months of ambient exposure to untreated air.