Epitaxial Growth Of Thin Layers Research Articles

Growth of Vanadium and Vanadium Oxide on a Rh(110) Surface

We have studied the epitaxial growth of thin layers of vanadium and vanadium oxide on a Rh(110) surface with low-energy electron diffraction (LEED), low-energy electron microscopy (LEEM), Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS). Up to six monolayers of V/VOx were deposited with temperatures varying between 370 and 770 K. For V deposition, (1 × n) and (n × 1) overlayers with n = 2 and 4 are observed. For the deposition of 3 MLE of VOx, a (12 × 1) structure is obtained as a stable structure. XPS of V 2p3/2 reveals the simultaneous presence of an oxidic and a metallic or strongly reduced (V2+) V component.

Epitaxy and structural properties of (V,Bi,Sb) 2Te3 layers exhibiting the quantum anomalous Hall effect

(Bi,Sb)${}_{2}$Te${}_{3}$ layers doped with Vanadium are ferromagnetic topological insulators exhibiting the quantum anomalous Hall effect (QAHE) at low temperatures. The Hall resistivity is quantized to h/e${}^{2}$ without an external magnetic field. The authors succeeded in reproducible epitaxial growth of thin layers, with an optimized Sb content in a narrow range around 80% showing the QAHE. Such layers grown on Si or InP substrates and with or without a protecting Te cap show quantization. The QAHE persists independently of the interfaces between cap, layer and substrate, limited crystalline quality, and layer degradation, confirming the robustness of the quantum anomalous Hall effect.

Sixteen years GaN on Si

GaN, the basis of high brightness LEDs and high power, high frequency FET's has developed to the second important semiconductor after Si. Although epitaxial growth of thin layers on sapphire has been developed already in the late 1980s the growth on Si, which offers lower cost and new application fields, was hampered mostly by thermal mismatch and chemical incompatibility leading to destructive melt‐back etching. In the last 16 years, GaN on Si has developed from a niche academic work to part of GaN mainstream technology. This article gives an overview on the breakthrough developments and different methods to solve the problems associated with GaN growth on Si as well as an overview on the different application fields.

Single photon emission from impurity centers in AlGaAs epilayers on Ge and Si substrates

We show that the epitaxial growth of thin layers of AlGaAs on Ge and Si substrates allows to obtain single photon sources by exploiting the sparse and unintentional contamination with acceptors of the AlGaAs. Very bright and sharp single photoluminescence lines are observed in confocal microscopy. These lines behave very much as single excitons in quantum dots, but their implementation is by far much easier, since it does not require 3D nucleation. The photon antibunching is demonstrated by time resolved Hanbury Brown and Twiss measurements.

Cooperative and competitive concurrency in scientific computing. A full open-source upgrade of the program for dynamical calculations of RHEED intensity oscillations

Cooperative and competitive concurrency in scientific computing. A full open-source upgrade of the program for dynamical calculations of RHEED intensity oscillations

Analysis of ambient gas influence on silicon layers crystallized by means of LPE

Epitaxial growth of thin layers from the liquid phase can occur with the use of solutions saturated under different ambient gases. Most often this process takes place in a vacuum or gaseous atmosphere of hydrogen or argon. As the experimental data show, the morphology of crystallized layers is determined by the ambient type in which the process occurs.The cohesion energy responsible for epitaxial lateral deposition processes on the substrate surface depends on the surface free energy which is a measure of attraction of the solution atoms by substrate atoms. In the case of crystallization of an epitaxial lateral layer of Si on a substrate partially masked with dielectric, the chemical potentials of atoms in the neighboring phases (determining the interface evolution) are not without influence on the relaxation velocity of the saturated liquid phase, and on the horizontal and vertical growth rate.The aim of the investigation was to analyze experimentally the influence of the ambient gases used during the LPE growth on the cohesion of the Sn–Si solution with substrates applied for the lateral epitaxial growth of Si layers. This work presents comparative temperature analysis of the wetting angle of such surfaces as Si, SiO2 and SiNx by the Sn–Si solution.

X-ray photoelectron spectroscopy of polymorphous thallous halides

A comparative x-ray photoelectron spectroscopy study of thallous chloride and thallous bromide in their simple cubic and face centered cubic crystallographic structures is reported. Simple cubic structure is the normal phase and a face centered structure is obtained by epitaxial growth of thin layers on potassium bromide substrate. The x-ray photoelectron spectroscopy appears to be able to distinguish these structural modifications. From one structure to another slight differences are found between the separation of cation and anion core energy levels; the use of an electrostatic point charge model leads us to attribute a more covalent bond in the fcc structures as compared to the sc ones. The evolution of the main structures in the valence band from sc to fcc crystals and from compound to compound are discussed in comparison with available KKR density of states calculations; the general shape of the valence bands as well as the trends in the sequences are fairly well reproduced.