Formation of Crystalline Germanium Nanoclusters in a Silica Xerogel Matrix from an Organogermanium Precursor

Abstract

Addition of the organogermanium compound, Me3GeS(CH2)3Si(OMe)3, to a modified, conventional sol−gel formulation gives a silica xerogel doped with this molecular species. Subsequent thermal treatment of this molecularly doped xerogel under oxidizing then reducing conditions affords nanoclusters of Ge highly dispersed throughout the bulk of the xerogel matrix. Under appropriate conditions, Ge nanoclusters having an average diameter of ca. 68 Å can be formed by this procedure. Characterization of this nanocomposite material by TEM, HRTEM, EDS, XRD, micro-Raman spectroscopy, electron diffraction, and UV−visible spectroscopy indicates that the Ge nanoclusters are highly crystalline and exhibit optical properties consistent with those expected when quantum confinement effects are operative.

Structure and stability of germanium nanoparticles

“…The pressure exerted on the nanoparticle core by the surface can induce an amorphous to ST12 transition, for clusters with diameters smaller than 2.5-3.0 nm. This may explain why different types of structures are seen in experiments using chemical preparation methods [5,7,8] versus physical vapor deposition methods [13,14]. According to our calculations, chemical methods should always yield diamond structures, consistent with the results of H. W. Lee et al [35].…”

“…Here we address these issues for the case of small Ge dots (1-3 nm), whose atomic structure is the most controversial amongst those of group IV and II-VI semiconductors. While some preparation techniques, including chemical methods [5][6][7][8][9], yield diamond-like Ge dots irrespective of size, several experiments [10][11][12] suggest a structural transition, as the dot diameter becomes smaller than 4-5 nm. In particular, some experiments [13,14] using vapor deposition techniques indicate a change from a cubic diamond (DIA) to a tetragonal structure, possibly ST12, in contrast to the behavior found for Si [15][16][17] and other II-VI dots [18,19].…”

Highly Efficient Synthesis of Boron‐ and Germanium‐Substituted Unsymmetrical Disilazanes

“…Organogermanium compounds have also aroused much interest in various fields recently (e.g., semiconductors in the electronic industry, nanocomposite materials, and pharmaceuticals) , . However, the applications of this class of compounds are still under investigation.…”

Nanocrystal formation for non-volatile memory application

“…Most of the early reports on the synthesis of nanocrystalline materials by PLD have been performed in an inert gas environment that promotes clustering in the gas phase. 80 The formation of Ge nanoparticles embedded in a GeO 2 matrix has also been demonstrated using a reactive PLD technique, under a background pressure of reactive gas. 81 and the enhanced adatom mobility contributes to enhanced nucleation process.…”