Epitaxial growth and surface reconstruction of CrSb(0001)

Smooth CrSb(0001) films have been grown by molecular beam epitaxy on MnSb(0001) – GaAs(111) substrates. CrSb(0001) shows (2 × 2), triple domain (1 × 4) and (√3×√3)R30° reconstructed surfaces as well as a (1 × 1) phase. The dependence of reconstruction on substrate temperature and incident fluxes is very similar to MnSb(0001)

In situ transmission electron microscopy study on the epitaxial growth of CoSi2 on Si(111) at temperatures below 150 °C

We report an in situ transmission electron microscopy study on the epitaxial growth of CoSi2 on Si(111) from a 10-nm-thick amorphous mixture of Co and Si in the ratio 1:2 which was formed by codeposition of Co and Si near room temperature. Nuclei of CoSi2 are observed in the as-deposited film. These nuclei are epitaxial and extend through the whole film thickness. Upon annealing, these columnar epitaxial CoSi2 grains grow laterally at temperatures as low as 50 °C. The kinetics of this lateral epitaxial growth was studied at temperatures between 50 and 150 °C. The activation energy of the growth process is 0.8±0.1 eV

Inhomogeneous low temperature epitaxial breakdown during Si overgrowth of GeSi quantum dots

Low temperature epitaxial breakdown of inhomogeneously strained Si capping layers is investigated. By growing Si films on coherently strained GeSi quantum dot surfaces, we differentiate effects of surface roughness, strain, and growth orientation on the mechanism of epitaxial breakdown. Using atomic force microscopy and high resolution cross-sectional transmission electron microscopy we find that while local lattice strain up to 2% has a negligible effect, growth on higher-index facets such as {113} significantly reduces the local breakdown thickness. Nanoscale growth mound formation is observed above all facet orientations. Since diffusion lengths depend directly on the surface orientation, we relate the variation in epitaxial thickness to the low temperature stability of specific growth facets and on the average size of kinetically limited growth mounds.Comment: 6 pages, 6 figures, submitted to the Journal of Applied Physic

Epitaxial growth of topological insulator Bi2Se3 film on Si(111) with atomically sharp interface

Atomically sharp epitaxial growth of Bi2Se3 films is achieved on Si (111) substrate with MBE (Molecular Beam Epitaxy). Two-step growth process is found to be a key to achieve interfacial-layer-free epitaxial Bi2Se3 films on Si substrates. With a single-step high temperature growth, second phase clusters are formed at an early stage. On the other hand, with low temperature growth, the film tends to be disordered even in the absence of a second phase. With a low temperature initial growth followed by a high temperature growth, second-phase-free atomically sharp interface is obtained between Bi2Se3 and Si substrate, as verified by RHEED (Reflection High Energy Electron Diffraction), TEM (Transmission Electron Microscopy) and XRD (X-Ray Diffraction). The lattice constant of Bi2Se3 is observed to relax to its bulk value during the first quintuple layer according to RHEED analysis, implying the absence of strain from the substrate. TEM shows a fully epitaxial structure of Bi2Se3 film down to the first quintuple layer without any second phase or an amorphous layer.Comment: 20 pages, 7 figure

Low-threshold room-temperature embedded heterostructure lasers

Room-temperature embedded double-heterostructure injection lasers have been fabricated using selective liquid phase epitaxial growth. Threshold current densities as low as 1.5 kA/cm^2 have been achieved in lasers grown through stripe windows opened in epitaxial GaAlAs masks

Island Distance in One-Dimensional Epitaxial Growth

The typical island distance $\ell$ in submonlayer epitaxial growth depends on the growth conditions via an exponent $\gamma$. This exponent is known to depend on the substrate dimensionality, the dimension of the islands, and the size $i^*$ of the critical nucleus for island formation. In this paper we study the dependence of $\gamma$ on $i^*$ in one--dimensional epitaxial growth. We derive that $\gamma = i^*/(2i^* + 3)$ for $i^*\geq 2$ and confirm this result by computer simulations.Comment: 5 pages, 3 figures, uses revtex, psfig, 'Note added in proof' appende

Growth of Large Domain Epitaxial Graphene on the C-Face of SiC

Growth of epitaxial graphene on the C-face of SiC has been investigated. Using a confinement controlled sublimation (CCS) method, we have achieved well controlled growth and been able to observe propagation of uniform monolayer graphene. Surface patterns uncover two important aspects of the growth, i.e. carbon diffusion and stoichiometric requirement. Moreover, a new "stepdown" growth mode has been discovered. Via this mode, monolayer graphene domains can have an area of hundreds of square micrometers, while, most importantly, step bunching is avoided and the initial uniformly stepped SiC surface is preserved. The stepdown growth provides a possible route towards uniform epitaxial graphene in wafer size without compromising the initial flat surface morphology of SiC.Comment: 18 pages, 8 figure