  Atomically thin one dimensional (1D) van der Waals wires of transition metal
monochalocogenides (TMMs) have been anticipated as promising building blocks
for integrated nanoelectronics. While reliable production of TMM nanowires has
eluded scientists over the past few decades, we finally demonstrated a bottom
up fabrication of MoTe nanowires inside carbon nanotubes (CNTs). Still, the
current synthesis method is based on vacuum annealing of reactive MoTe2, and
limits access to a variety of TMMs. Here we report an expanded framework for
high yield synthesis of the 1D tellurides including WTe, an unprecedented
family of TMMs. Experimental and theoretical analyses revealed that the choice
of suitable metal oxides as a precursor provides useful yield for their
characterization. These TMM nanowires exhibit a significant optical absorption
in the visible light region. More important, electronic properties of CNTs can
be tuned by encapsulating different TMM nanowires.
