Solution−Liquid−Solid Growth of Indium Phosphide Fibers from Organometallic Precursors:  Elucidation of Molecular and Nonmolecular Components of the Pathway

Abstract

Methanolysis of { t -Bu 2 In[μ-P(SiMe 3 ) 2 ]} 2 ( 1 ) in aromatic solvents gives polycrystalline InP fibers (dimensions 10−100 nm × 50−1000 nm) at 111−203 °C. The chemical pathway consists of a molecular component, in which precursor substituents are eliminated, and a nonmolecular component, in which the InP crystal lattices are assembled. The two components working in concert comprise the solution−liquid−solid (SLS) mechanism. The molecular component proceeds through a sequence of isolated and fully characterized intermediates: 1 → [ t -Bu 2 In(μ-OMe)] 2 ( 2 ) → [ t -Bu 2 In(μ-PHSiMe 3 )] 2 ( 3 ) → 2 → [ t -Bu 2 In(μ-PH 2 )] 3 ( 4 ). Complex 4, which is alternatively prepared from t -Bu 3 In and PH 3, undergoes alkane elimination, the last steps of which are catalyzed by the protic reagent MeOH, PhSH, Et 2 NH, or PhCO 2 H. In the subsequent nonmolecular component of the pathway, the resulting (InP) n fragments dissolve into a dispersion of molten In droplets, and recrystallize as the InP fibers. Important criteria are identified for crystal growth of covalent nonmolecular solids from (organic) solution. The outcomes of other solution-phase semiconductor syntheses are rationalized according to the functioning of molecular and nonmolecular pathway components of the kind identified here.