Germanium nanoparticles from solvated atoms: synthesis and characterization

Abstract

Germanium nanoparticles were synthesized by the chemical liquid deposition method (CLD) in which the Ge atoms, produced resistively, were co-deposited with 2-propanol, acetone and tetrahydrofurane vapors to obtain colloidal dispersions. The colloidal dispersions were characterized by UV-vis spectrophotometry, transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction ( SAED) and Infrared Spectroscopy ( FTIR) techniques. The Germanium colloids are, in general, kinetically unstable. Strong absorption bands in the UV region suggest that nanoparticles obtained by this procedure exhibit quantum confinement. In the Ge colloids, the particle size distribution is highly sensitive to concentration change. For example, the TEM measurements revealed for the Ge-2-propanol colloid, particle sizes close to 3 nm for a concentration of 10) 3 M and 30 nm for a concentration of 10) 2 M. The HRTEM and SAED showed the high crystallinity of the nanoparticles, and it was possible to observe the typical lattice spaces of a diamond cubic Ge structure. The FTIR studies revealed the Ge-organic nature of the particles surface. Mechanisms and structures have been proposed for surface reactions.