Ge
1–
x
Sn
x
nanowires incorporating a large amount of Sn would be useful
for mobility enhancement in nanoelectronic devices, a definitive transition
to a direct bandgap for application in optoelectronic devices and
to increase the efficiency of the GeSn-based photonic devices. Here
we report the catalytic bottom-up fabrication of Ge
1–
x
Sn
x
nanowires with very
high Sn incorporation (
x
> 0.3). These nanowires
are grown in supercritical toluene under high pressure (21 MPa). The
introduction of high pressure in the vapor–liquid–solid
(VLS) like growth regime resulted in a substantial increase of Sn
incorporation in the nanowires, with a Sn content ranging between
10 and 35 atom %. The incorporation of Sn in the nanowires was found
to be inversely related to nanowire diameter; a high Sn content of
35 atom % was achieved in very thin Ge
1–
x
Sn
x
nanowires with diameters close
to 20 nm. Sn was found to be homogeneously distributed throughout
the body of the nanowires, without apparent clustering or segregation.
The large inclusion of Sn in the nanowires could be attributed to
the nanowire growth kinetics and small nanowire diameters, resulting
in increased solubility of Sn in Ge at the metastable liquid–solid
interface under high pressure. Electrical investigation of the Ge
1–
x
Sn
x
(
x
= 0.10) nanowires synthesized by the supercritical fluid
approach revealed their potential in nanoelectronics and sensor-based
applications.