Berlin 2018 – wissenschaftliches Programm

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 3: Crystal Structure, Defects, Real Structure and Microstructure in Materials

KFM 3.4: Vortrag

Montag, 12. März 2018, 10:30–10:50, E 124

Zinc-blende and wurtzite phase formation in indium phosphide nanowires grown by template-assisted selective epitaxy — •Philipp Staudinger¹, Stephan Wirths¹, Marta D. Rossell^{1, 2}, Marilyne Sousa¹, Kirsten E. Moselund¹, and Heinz Schmid¹ — ¹IBM Research Zuerich, 8803 Rueschlikon, Switzerland — ²Electron Microscopy Center, EMPA, 8600 Duebendorf, Switzerland

Group III-V semiconductor nanowires (NWs) are expected to provide a platform for a wide range of future applications such as high-performance field effect transistors and optoelectronic devices. Nanostructures offer a new type of band structure engineering based on the formation of zinc-blende (ZB) - wurtzite (WZ) polytypism. These crystal phases are distinctively different in terms of physical properties facilitating applications such as direct bandgap materials in the 495-570 nm wavelength regime. However, the crystallographic quality of NWs remains difficult to control, resulting typically in the formation of a high number of planar defects. So far, using Template-Assisted Selective Epitaxy (TASE), the growth of WZ phase has not been observed.

We demonstrate that both WZ and ZB crystal phases can be obtained using TASE. InP NWs were selectively grown using metal organic vapor phase epitaxy at temperatures of 625 °C and a V/III ratio of 50 inside predefined hollow oxide templates of varying dimensions. The crystal phase was determined by micro photoluminescence spectroscopy along with scanning transmission electron microscopy. Both ZB and WZ phases were found in nearly pure form, giving promise for novel device applications such as high efficient green LEDs.