Growth and Structure of Chemically Vapor Deposited Ge Nanowires on Si Substrates

Abstract

Chemical vapor deposition by Au-catalyzed decomposition of GeH 4 has been used to grow Ge nanowires on single-crystal silicon. The nanowires grow over the temperature range ∼320−380 °C under the conditions used, probably by the vapor−liquid−solid (VLS) process. The lowtemperature growth aids integration with conventional electronic devices. At the optimum temperature near 320 °C, many of the nanowires are epitaxially oriented with the substrate crystal structure, growing in 〈111〉 directionssat an oblique angle on (001)-oriented Si substrates and nearly vertically on Si(111). High-resolution transmission electron microscopy confirms that the nanowires grow in the 〈111〉 directions and that the crystal lattice continues from the substrate into the nanowires. Transmission electron microscopy also shows that the nanowires contain very few crystalline defects. Au-containing nanoparticles (possibly γ-phase Au 0.6 Ge 0.4 ) are found at the tips of the nanowires, but no Au can be detected within the nanowires themselves.

Structural and optical properties of axial silicon-germanium nanowire heterojunctions

“…[15][16][17][18] Another promising approach is to use one-dimensional (1D) growth in the form of nanowires (NWs) produced by the vapor-liquid-solid (VLS) growth mode or similar techniques. [19][20][21][22] These axial Si/Ge NW HJs with the heterointerfaces perpendicular to the NW axes have a reduced heterointerface area compared to radial or "core-shell" NW HJs, where the Si/Ge heterointerfaces are parallel to the NW axes. [22][23][24] Since Ge has a larger lattice constant (5.658 Å ) compared to Si (5.431 Å ), it was proposed that in axial Si/Ge NW HJs strain created by the lattice mismatch between Si and Ge can partially be relieved at the heterointerfaces by the lateral expansion of a Ge segment of the NW.…”

Single crystalline and core–shell indium-catalyzed germanium nanowires—a systematic thermal CVD growth study

“…Indeed, germanium nanowire field effect devices may exhibit better performance than planar and nanowire silicon technology. Moreover, germanium nanowires can be grown on silicon substrates, thereby guaranteeing integration with silicon technology [11][12][13].…”

GaAs:Mn Nanowires Grown by Molecular Beam Epitaxy of (Ga,Mn)As at MnAs Segregation Conditions

“…binary and ternary III-V and II-VI semiconductors). 1,[10][11][12] However, there is quite a large variety of materials that do not need any catalyst for NW growth, e.g. GaN 13 or ZnO 14 .…”