Metal‐Iodide‐Mediated CVT Growth of Form V Red Phosphorus Wires

ABSTRACT

One‐dimensional phosphorus allotropes remain difficult to synthesize despite their promise for (opto)electronics. Form V red phosphorus (Hittorf's phosphorus), composed of tubular phosphorus chains, has mainly been obtained as platelets or bulk crystals, limiting studies of anisotropic growth and transport. Here, AgI‐assisted chemical vapor transport enables on‐substrate growth of high‐aspect‐ratio red‐phosphorus wires extending hundreds of micrometers. SAED identifies multiple individual wires as Form V, while HRTEM‐FFT analysis supports preferential [010] growth along the tubular chains. PXRD/GID and a weak Raman band near 486 cm ^{− 1} provide complementary evidence, although the population‐wide Form V fraction was not quantified. SEM analysis reveals a log‐normal diameter distribution with a median of 433 nm ( n = 175). EDX, XPS, and cross‐sectional TEM‐EDX detect residual Ag/I species enriched near wire surfaces. Together with AgI‐free controls, these results support AgI‐mediated heterogeneous nucleation, pending in situ verification. A two‐terminal device on a ∼1.2 µm wire shows linear I – V behavior and an effective resistivity of 91.3 Ω cm, excluding continuous metallic Ag shorting, although contact and scattering contributions were not deconvoluted. This work establishes an on‐substrate route to Form V red‐phosphorus wires and a platform for future gate‐dependent transport studies.