Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 35: Poster Session II (Polymeric biomolecular films; Nanostructures; Electronic structure; Spin-orbit interaction; Phase transitions; Surface chemical reactions; Heterogeneous catalysis; Particles and clusters; Surface magnetism; Electron and spin dynamics; Surface dynamics; Methods; Electronic structure theory; Functional molecules)
O 35.15: Poster
Dienstag, 27. März 2012, 18:15–21:45, Poster B
p- and n-type Silicon Nanowires from Metal-Assisted Chemical Etching — •U. Heiden1, J. Sölle1, S. Weidemann1, R. Heimburger2, T Teubner2, T. Boeck2, R. Fornari2, and S.F. Fischer1 — 1Neue Materialien, Institut für Physik, Humboldt-University zu Berlin, D-10099 Berlin — 2Leibniz-Institut für Kristallzüchtung, Max-Born-Str. 2, D-12489 Berlin
Metal-assisted chemical etching (MACE) is a top-down procedure to form silicon nanowires (SiNWs) [1]. A precise control of etching parameters and the understanding of their influence on the nanowire morphology are topical research issues. They are extremely important to achieve process reproducibility.
Vertical and single crystalline SiNWs were produced with a two-step MACE procedure. Silver nanoparticles are used as catalyst. The etchant includes hydrofluoric acid (HF) and hydrogen peroxide (H2O2). We investigate the difference between highly doped p and n SiNWs regarding to the length, porosity and their density on the wafer.
p-type SiNWs are longer and show a higher density on the wafer compared to n-type NWs. Longer etching times lead to longer NW lengths. Increasing the concentration of H2O2 in the etchant, accelerates the etching reaction and decreases the NW density. A higher growth rate causes the NWs to stick together at the top and form sheaves which is in accordance with the previous report in [1].
[1] M. Zhang et al., J. Phys. Chem. C 112, 4444-4450 (2008).