Electron parametric resonance identification of the SbGa heteroantisite defect in GaAs:Sb

GaAs doped with antimony (Sb) to a level of 10 high 19 cm high minus 3 has been studied by electron paramagnetic resoncance (EPR). A new EPR spectrum has been discovered which is identified as the Sb sub Ga heteroantisite defect. The electronic structure of this defect is practically indentical whith that of the intrinsic-anion antisite devects in GaP, GaAs, and InP. The EPR results show that Sb can be incorporated as an electrically active defect and therefore is not a suitable isovalent dopant in the growth of low-dislocation-density semi-insulating GaAs

Interface oxidative structural transitions in graphene growth on SiC (0001)

The structural transition from a three-dimensional SiC lattice to a two-dimensional graphene sheet is a crucial element in the growth mechanism of graphene on SiC. An interfacial defective transition layer near the surface of the SiC substrate is believed to be an intermediate structure for graphene layer formation. The transition layer consists of SiO xC y, vacancies, and other defects in the SiC lattice, which result from Si evaporation via thermal degradation of the SiC lattice and oxidation reactions of residual oxygen and other oxygen containing molecules on the SiC surface at high temperatures. This partially oxidized and structurally degraded SiC lattice layer is formed at temperatures lower than the graphene growth temperature but then decomposes with increasing temperature, leading to graphene formation. Then, the growth mechanism for graphene on SiC (0001) in high vacuum consists of multiple steps, including Si removal by thermal decomposition and oxidation, collapsing of the near surface SiC lattice, conversion from sp 3 to sp 2 carbon, and an increase in the degree of low-dimensional graphitization. The proposed atomic scale mechanism is able to explain experimental phenomena in graphene/SiC structural growth, such as graphene coverage at step edges, growth environment effects, graphene domain size, and thickness variations. © 2012 American Chemical Society.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Impact of growth temperature on InAs/GaInSb strained layer superlattices for very long wavelength infrared detection

We explore the optimum growth space for a 47.0A ° InAs/21.5A ° Ga0.75In0.25Sb superlattices (SLs) designed for the maximum Auger suppression for a very long wavelength infrared gap. Our growth process produces a consistent gap of 5065meV. However, SL quality is sensitive to the growth temperature (Tg). For the SLs grown at 390 470 C, a photoresponse signal gradually increases as Tg increases from 400 to 440 C. Outside this temperature window, the SL quality deteriorates very rapidly. All SLs were n-type with mobility of 10 000 V/cm2 and 300K recombination lifetime of 70 ns for an optimized SL