Formation and Stabilization of Single-Crystalline Metastable AuGe Phases in Ge Nanowires

Journal Article · Fri Jul 22 04:00:00 EDT 2011 · Nanotechnology

DOI:https://doi.org/10.1088/0957-4484/22/29/295605· OSTI ID:1024329

Sutter, E; Sutter, P

We use in situ observations by variable temperature transmission electron microscopy on AuGe alloy drops at the tips of Ge nanowires (NWs) with systematically varying composition to demonstrate the controlled formation of metastable solid phases integrated in NWs. The process, which operates in the regime of vapor-liquid-solid growth, involves a size-dependent depression of the alloy liquidus at the nanoscale that leads to extremely Ge-rich AuGe melts at low temperatures. During slow cooling, these liquid AuGe alloy drops show pronounced departures from equilibrium, i.e., a frustrated phase separation of Ge into the adjacent solid NW, and ultimately crystallize as single-crystalline segments of metastable {gamma}-AuGe. Our findings demonstrate a general avenue for synthesizing NW heterostructures containing stable and metastable solid phases, applicable to a wide range of materials of which NWs form by the vapor-liquid-solid method.

• Research Organization: Brookhaven National Laboratory (BNL) Center for Functional Nanomaterials
• Sponsoring Organization: DOE - OFFICE OF SCIENCE
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1024329
• Report Number(s): BNL--95278-2011-JA; KC020401H
• Journal Information: Nanotechnology, Journal Name: Nanotechnology Journal Issue: 29 Vol. 22; ISSN 0957-4484
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
GERMANIUM
GERMANIUM ALLOYS
GOLD ALLOYS
HETEROJUNCTIONS
QUANTUM WIRES
STABILIZATION
TRANSMISSION ELECTRON MICROSCOPY
functional nanomaterials