Perpendicular growth of catalyst-free germanium nanowire arrays

Abstract

5High yields of single-crystalline Ge nanowires (NWs) were synthesized through the thermal decomposition of diphenylgermane (DPG) in the vapor phase of a high boiling point organic solvent. The NWs were single crystal and ranged from 7 to 15 nm and 0.5-10 µm in diameter and length 10 respectively. Catalyst-free growth only occured in areas exposed to the organic vapor, with no growth occurring in the liquid phase. NW growth was fully localizable to surfaces heated within a critical nucleation temperature range. High density, perpendicular arrays of Ge NWs were subsequently grown from 15 ITO coated substrates. This approach represents a viable and convenient route toward orientated arrays of catalyst-free Ge NWs for high-performance device applications.

Role of Defects and Growth Directions in the Formation of Periodically Twinned and Kinked Unseeded Germanium Nanowires

“…who investigated the formation of unseeded germanium nanowires in the liquid phase of high boiling point solvents. 19,21 While increased reactions temperatures were found to alter the relative percentage of each type of wire, the diameter ranges of each wire type remained constant.…”

“…21 In a typical synthesis, 10 ml of 5 squalene (or squalane) was weighed out into a flask and connected to a schlenk line via a water condenser. The set-up was placed inside a three zone furnace and the system was heated to 125 °C using a ten minute ramp period under vacuum.…”

“…21 Examples of, and reasoning for, lateral, longitudinal and more complex faults seen in the NWs are presented and an increase in their relative frequency as a function of 20 reaction temperature and solvent is detailed. Tortuous NWs are examined and NW kinking is found to originate from interplay between NWs tending to grow along preferred crystallographic axes and NW defects being perpendicular to the NW growth direction.…”

High Density Germanium Nanowire Growth Directly from Copper Foil by Self-Induced Solid Seeding

“…31 5 ml squalene (≥98 % Aldrich) was weighed into a custom made Pyrex, round bottomed flask. The Cu substrate was then placed into the flask which was attached to a Schlenk line setup via a water condenser.…”

Complete Synthesis of Germanium Nanocrystal Encrusted Carbon Colloids in Supercritical CO2 and their Superhydrophobic Properties

“…We have recently shown that decomposition of organogermane/silane precursors in both vapor phase and supercritical systems results in spontaneous nucleation of nanocrystalline structures without the requirement for catalyst particles. 21,22 Here the carbon colloids act as preferential sites for nanocrystal nucleation with the extent of nanocrystal coverage and density shown to be a function of precursor concentration. The addition of the organometallic precursor also serves to induce a phase change in the spheres from amorphous carbon to a crystalline graphitic phase.…”