X-ray method to study temperature-dependent stripe domains in MnAs/GaAs(001)

MnAs films grown on GaAs (001) exhibit a progressive transition between hexagonal (ferromagnetic) and orthorhombic (paramagnetic) phases at wide temperature range instead of abrupt transition during the first-order phase transition. The coexistence of two phases is favored by the anisotropic strain arising from the constraint on the MnAs films imposed by the substrate. This phase coexistence occurs in ordered arrangement alternating periodic terrace steps. We present here a method to study the surface morphology throughout this transition by means of specular and diffuse scattering of soft x-rays, tuning the photon energy at the Mn 2p resonance. The results show the long-range arrangement of the periodic stripe-like structure during the phase coexistence and its period remains constant, in agreement with previous results using other techniques.Comment: 4 pages, 4 figures, submitted to Applied Physics Letter

Three-dimensional mapping of the strain anisotropy in self-assembled quantum-wires by grazing incidence x-ray diffraction

Three-dimensional strain mapping of InAs self-assembled nanowires on an InP substrate using grazing incidence x-ray diffraction is reported. A remarkable anisotropy was observed for the strain components, parallel [-220] and perpendicular [220] to the wire axis. The highest strain relaxation was measured along the [220] direction. The relationship between the interatomic distances along the [-220] and [220] directions, for each z position (height) in the nanostructure, was obtained by angular scans in the vicinity of the (040) reciprocal lattice point. (C) 2004 American Institute of Physics.85163581358

Strain relaxation and stress-driven interdiffusion in InAs/InGaAs/InP nanowires

The authors have investigated strain relaxation in InAs/InGaAs/InP nanowires (NW's). Transmission electron microscopy images show an additional stress field attributed to compositional modulation in the ternary layer, which disrupts NW formation and drives Ga interdiffusion into InAs, according to grazing incidence x-Ray diffraction under anomalous scattering conditions. The strain profile along the NW, however, is not significantly affected when interdiffusion is considered. Results show that the InAs NW energetic stability is preserved with the introduction of ternary buffer layer in the structure. (c) 2007 American Institute of Physics.91

X-ray Diffraction Mapping Of Strain Fields And Chemical Composition Of Sige:si(001) Quantum Dot Molecules

A variety of surface morphologies can be formed by controlling kinetic parameters during heteroepitaxial film growth. The system reported is a Si0.7 Ge0.3 film grown by molecular beam epitaxy at 550°C and a 1 s deposition rate, producing quantum dot molecule (QDM) structures. These nanostructures are very uniform in size and shape, allowing strain mapping and chemical composition evaluation by means of anomalous x-ray diffraction in a grazing incidence geometry. Tensile and compressed regions coexist inside QDMs, in accordance with the finite-element calculations of lattice relaxation. The Ge content was found to vary significantly within the structures, and to be quite different from the nominal composition. © 2006 The American Physical Society.7312Chen, K.M., (1995) Appl. Phys. Lett., 66, p. 34. , APPLAB 0003-6951 10.1063/1.114172Goldfarb, I., (1997) Phys. Rev. Lett., 78, p. 3959. , PRLTAO 0031-9007 10.1103/PhysRevLett.78.3959Mo, Y.-W., (1990) Phys. Rev. Lett., 65, p. 1020. , PRLTAO 0031-9007 10.1103/PhysRevLett.65.1020Tomitori, M., (1994) Appl. Surf. Sci., 76-77, p. 322. , ASUSEE 0169-4332Floro, J.A., (1998) Phys. Rev. Lett., 80, p. 4717. , PRLTAO 0031-9007 10.1103/PhysRevLett.80.4717Ross, F.M., (1998) Phys. Rev. Lett., 80, p. 984. , PRLTAO 0031-9007 10.1103/PhysRevLett.80.984Medeiros-Ribeiro, G., (1998) Science, 279, p. 353. , SCIEAS 0036-8075 10.1126/science.279.5349.353Chaparro, S.A., (1999) Phys. Rev. Lett., 83, p. 1199. , PRLTAO 0031-9007 10.1103/PhysRevLett.83.1199Denker, U., (2005) Appl. Phys. Lett., 772, p. 599. , APPLAB 0003-6951Gray, J.L., (2002) Appl. Phys. Lett., 81, p. 2445. , APPLAB 0003-6951 10.1063/1.1509094Vandervelde, J.T.E., (2003) Appl. Phys. Lett., 83, p. 2505. , APPLAB 0003-6951Jesson, D.E., (1996) Phys. Rev. Lett., 77, p. 1330. , PRLTAO 0031-9007 10.1103/PhysRevLett.77.1330Gray, J.L., (2004) Phys. Rev. Lett., 92, p. 135504. , PRLTAO 0031-9007 10.1103/PhysRevLett.92.135504Schülli, T.U., (2003) Phys. Rev. Lett., 90, p. 066105. , PRLTAO. 0031-9007. 10.1103/PhysRevLett.90.066105Malachias, A., (2003) Phys. Rev. Lett., 91, p. 176101. , PRLTAO 0031-9007 10.1103/PhysRevLett.91.176101Magalhães-Paniago, R., (2002) Phys. Rev. B, 66, p. 245312. , PRBMDO. 0163-1829. 10.1103/PhysRevB.66.245312Krause, B., (2005) Phys. Rev. B, 72, p. 085339. , PRBMDO 0163-1829 10.1103/PhysRevB.72.085339Zhang, Y., (2001) J. Appl. Phys., 90, p. 4748. , JAPIAU 0021-8979 10.1063/1.1407311Gray, J.L., (2005) Phys. Rev. B, 72, p. 155323. , PRBMDO 0163-1829 10.1103/PhysRevB.72.155323Tersoff, J., (1998) Phys. Rev. Lett., 81, p. 3183. , PRLTAO 0031-9007 10.1103/PhysRevLett.81.318

Size Evolution of Ordered SiGe Islands Grown by Surface Thermal Diffusion on Pit-Patterned Si(100) Surface

The ordered growth of self-assembled SiGe islands by surface thermal diffusion in ultra high vacuum from a lithographically etched Ge stripe on pit-patterned Si(100) surface has been experimentally investigated. The total surface coverage of Ge strongly depends on the distance from the source stripe, as quantitatively verified by Scanning Auger Microscopy. The size distribution of the islands as a function of the Ge coverage has been studied by coupling atomic force microscopy scans with Auger spectro-microscopy data. Our observations are consistent with a physical scenario where island positioning is essentially driven by energetic factors, which predominate with respect to the local kinetics of diffusion, and the growth evolution mainly depends on the local density of Ge atoms

Resonant X-ray Scattering From Self-assembled Inpgaas (001) Islands: Understanding The Chemical Structure Of Quaternary Quantum Dots

Lattice parameter profiles and the chemical structure of InP self-assembled islands grown on GaAs(001) were determined with x-ray resonant scattering. By accessing four different photon energies, near x-ray absorption edges of two of the atomic species present on the samples, composition maps of all four atomic constituents of these islands were obtained. This experiment was performed for samples grown at two different temperatures and the effect of temperature was associated to Ga-interdiffusion and strain relief in the dots. © 2008 American Institute of Physics.922Klimov, V.I., Mikhailovsky, A.A., Xu, S., Malko, A., Hollingsworth, J.A., Leatherdale, C.A., Eisler, H.-J., Imamoglu, A., (2000) Science, 290, p. 314. , See, e. g., SCIEAS 0036-8075 10.1126/science.290.5490.314, ();, Science SCIEAS 0036-8075 10.1126/science.1109815 308, 1158 (2005)Cullis, A.G., Norris, D.J., Walther, T., Migliorato, M.A., Hopkinson, M., (2002) Phys. Rev. B, 66, p. 081305. , PRBMDO 0163-1829 10.1103/PhysRevB.66.081305Kegel, I., Metzger, T.H., Fratzl, P., Peisl, J., Lorke, A., Garcia, J.M., Petroff, P.M., (1999) Europhys. Lett., 45, p. 222. , EULEEJ 0295-5075 10.1209/epl/i1999-00150-yGray, J.L., Singh, N., Elzey, D.M., Hull, R., Floro, J.A., (2004) Phys. Rev. Lett., 92, p. 135504. , PRLTAO 0031-9007 10.1103/PhysRevLett.92.135504Medeiros-Ribeiro, G., Williams, R.S., (2007) Nano Lett., 7, p. 223. , NALEFD 1530-6984 10.1021/nl062530kMalachias, A., Magalhães-Paniago, R., Neves, B.R.A., Rodrigues, W.N., Moreira, M.V.B., Pfannes, H.-D., De Oliveira, A.G., Metzger, T.H., (2001) Appl. Phys. Lett., 79, p. 4342. , APPLAB 0003-6951 10.1063/1.1427421Magalhães-Paniago, R., Medeiros-Ribeiro, G., Malachias, A., Kycia, S., Kamins, T.I., Stan Williams, R., Schülli, T.U., Bauer, G., (2002) Phys. Rev. B, 66, p. 245312. , PRBMDO 0163-1829 10.1103/PhysRevB.66.245312, ();, Phys. Rev. Lett. PRLTAO 0031-9007 10.1103/PhysRevLett.90.066105 90, 066105 (2003)Tchernycheva, M., Cirlin, G.E., Patriarche, G., Travers, L., Zwiller, V., Perinetti, U., Harmand, J.-C., (2007) Nano Lett., 7, p. 1500. , NALEFD 1530-6984, (Liu, N., Tersoff, J., Baklenov, O., Holmes Jr., A.L., Shih, C.K., (2000) Phys. Rev. Lett., 84, p. 334. , PRLTAO 0031-9007 10.1103/PhysRevLett.84.334Ribeiro, E., Maltez, R.L., Carvalho Jr., W., Ugarte, D., Medeiros-Ribeiro, G., (2002) Appl. Phys. Lett., 81, p. 2953. , APPLAB 0003-6951 10.1063/1.151321

Strain Relaxation And Stress-driven Interdiffusion In Inasingaasinp Nanowires

The authors have investigated strain relaxation in InAsInGaAsInP nanowires (NW's). Transmission electron microscopy images show an additional stress field attributed to compositional modulation in the ternary layer, which disrupts NW formation and drives Ga interdiffusion into InAs, according to grazing incidence x-Ray diffraction under anomalous scattering conditions. The strain profile along the NW, however, is not significantly affected when interdiffusion is considered. Results show that the InAs NW energetic stability is preserved with the introduction of ternary buffer layer in the structure. © 2007 American Institute of Physics.916Yoffe, A.D., (2001) Adv. Phys., 50, p. 1Brault, J., Gendry, M., Grenet, G., Hollinger, G., Dieres, Y., Benyattou, T., (1998) Appl. Phys. Lett., 73, p. 2932Yoon, H., Moon, Y., Lee, T., Yoon, E., Kim, Y., (1999) Appl. Phys. Lett., 74, p. 2029Ustinov, V.M., Weber, E.R., Ruvimov, S., Liliental-Weber, Z., Zhukov, A.E., Yu. Egorov, A., Kovsh, A.R., Kopev, P.S., (1998) Appl. Phys. Lett., 72, p. 362Li, H., Daniels-Race, T., Hasan, M.A., (2002) Appl. Phys. Lett., 80, p. 1367Suárez, F., Fuster, D., González, L., González, Y., García, J.M., Dotor, M.L., (2006) Appl. Phys. Lett., 89, p. 091123García, J.M., González, L., González, M.U., Silveira, J.P., González, Y., Briones, F., (2001) J. Cryst. Growth, 227, p. 975Saint-Girons, G., Michon, A., Sagnes, I., Beaudoin, G., Patriarche, G., (2006) Phys. Rev. B, 74, p. 245305Gutírrez, H.R., Cotta, M.A., Bortoleto, J.R.R., (2002) J. Appl. Phys., 92, p. 7523Kegel, I., Metzger, T.H., Lorke, A., Peisl, J., Stangl, J., Bauer, G., Garcia, J.M., Petroff, P.M., (2000) Phys. Rev. Lett., 85, p. 1694Gutírrez, H.R., Magalhães-Paniago, R., Bortoleto, J.R.R., Cotta, M.A., (2004) Appl. Phys. Lett., 85, p. 3581Sztucki, M., Schülli, T.U., Metzger, T.H., Beham, E., Schuh, D., Chamard, V., (2004) Superlattices Microstruct., 36, p. 11Malachias, A., Magalhães-Paniago, R., Kycia, S., Gahill, D., (2004) J. Appl. Phys., 96, p. 3234Gutírrez, H.R., Cotta, M.A., De Carvalho, M.G., (2001) Appl. Phys. Lett., 79, p. 3854Peiró, F., Ferrer, J.C., Cornet, A., Calamiotou, M., Georgakilas, A., (2003) Phys. Status Solidi A, 195, p. 32Bortoleto, J.R.R., Gutírrez, H.R., Cotta, M.A., Bettini, J., (2007) J. Appl. Phys., 101, p. 064907Bortoleto, J.R.R., Gutírrez, H.R., Cotta, M.A., Bettini, J., (2005) Appl. Phys. Lett., 87, p. 013105Henoc, P., Izrael, A., Quillec, M., Launois, H., (1982) Appl. Phys. Lett., 40, p. 96