Growth and characterization of LuAs films and nanostructures

Abstract

We report the growth and characterization of nearly lattice-matched LuAs/GaAs heterostructures. Electrical conductivity, optical transmission, and reflectivity measurements of epitaxial LuAs films indicate that LuAs is semimetallic, with a room-temperature resistivity of 90 μΩ cm. Cross-sectional transmission electron microscopy confirms that LuAs nucleates as self-assembled nanoparticles, which can be overgrown with high-quality GaAs. The growth and material properties are very similar to those of the more established ErAs/GaAs system; however, we observe important differences in the magnitude and wavelength of the peak optical transparency, making LuAs superior for certain device applications, particularly for thick epitaxially embedded Ohmic contacts that are transparent in the near-IR telecommunications window around 1.3 μm.

Temperature dependence of the electrical resistivity of LaxLu1-xAs

“…We previously reported the temperature-dependence resistivity of LuAs and LaAs films at 77-300 K temperature range. 15,16 Here we report the studies of the temperature-dependent electrical resistivity of these two compounds at 5-300 K range. We also investigated the effect of La concentration and the film thickness on the resistivity of La x Lu 1-x As ternary alloy films.…”

“…While the 10 ML LuAs is more strained to the GaAs lattice than 600 nm film, this additional strain impact the lattice constant of 10 ML films only slightly compared to the bulk phase (600 nm thick films) and thus does not have a significant effect on the residual resistivity of the 10 ML films. 16 Figure 2(b) shows the electrical resistivity of 10 ML (3 nm) La x Lu 1-x As with x = 0, 5, 9 and 15% La concentration. At 5 K, the residual resistivity is observable similar to the pure LuAs films and varies from ∼ 60 μ -cm for LuAs to ∼200 μ -cm for La x Lu 1-x As (x = 15%).…”

“…Film thickness was determined in-situ by reflection highenergy electron diffraction (RHEED) oscillations and confirmed ex-situ by X-ray diffraction (XRD) and cross-sectional transmission electron microscopy (XTEM). 15,16 Thick samples consisting of 600 nm of LuAs, 500 nm of LaAs and 500 nm of La 0.48 Lu 0.52 As were also investigated. The growth of thicker films is similar to the growth of thin 10 ML films, with the main difference being the integration of 10 ML top and bottom LuAs spacer layers surrounding the LaAs and La 0.48 Lu 0.52 As films to prevent interfacial instability.…”

Growth rate and surfactant-assisted enhancements of rare-earth arsenide InGaAs nanocomposites for terahertz generation

“…Prior studies of LuAs-based nanocomposites 21,37 indicate nucleation of LuAs nanoparticles before the formation of films when grown on zincblende iii-v materials, similar to other RE-V monopnictides. 53,54 The growth rate of the RE-As 42 and the amount deposited 21,[55][56][57] affect the density 096106-3 Salas et al…”

“…14,15 Candidate photoconductive materials are characterized by high resistivities, high carrier mobilities, and short carrier lifetimes. 16 Previous and current photoconductive materials work has focused mainly on low-temperaturegrown (LTG) GaAs, 17 superlattices of epitaxially embedded ErAs [18][19][20] and LuAs [21][22][23] nanoparticles in GaAs, and co-deposited nanoparticles of ErAs in a dilute-bismide matrix of GaAsBi. 24 The recent ErAs:GaAsBi approach reported by Bomberger et al is a noteworthy advance as these materials exhibited excellent dark resistivity and can be pumped with longer-wavelength sources, though more work is needed to achieve high carrier mobilities at the low growth temperatures that are required for dilute-bismide growth.…”