Monolithic gels have been produced by reaction of Si(NHMe)(4) with ammonia in THF solution and converted to high surface area aerogels by critical point drying with ammonia saturated diethylamine solvent.

Ordered macroporous films of nanocrystalline TiN and amorphous SiN x on silica substrates have been prepared. This involved infiltration of sacrificial templates of close-packed polystyrene microsphere arrays with precursor materials, followed by pyrolysis under ammonia to remove the template and form the ceramic materials. TiN was prepared from a sol-gel route, whereas SiN x was introduced using a Si(NHMe) 4 precursor solution. Hexane was found to be the solvent most compatible with the divinylbenzene-cross-linked polystyrene template and was used for both materials.

The formation of silicon nitride films using a sol-gel process and dip-coating is reported. The effect of a trifluoromethanesulfonic acid catalyst on condensation is investigated, and affects the behaviour of gels on heating. Smooth films can be obtained on silicon wafer substrates, and these can be built up using multiple dippings as the gelation process is irreversible. Firing at 1000 C produces amorphous silicon nitride films, though these contain some carbon and hydrogen and are sensitive to surface oxidation.

Exposure of solutions of Tb(N(SiMe 3 ) 2 ) 3 with SiCl(NEt 2 ) 3 in THF to dry ammonia results in polymeric xerogels. Heating these gels in ammonia leads to amorphous Tb:SiN x phosphors that exhibit bright green luminescence under UV irradiation. MAS-NMR and combustion analysis show the phosphors to be silicon nitride materials analogous to those typically produced by solgel routes. Photoluminescence behavior is similar to that of Tb:SiN x or Tb:SiO 2 films produced by ion implantation that show good electroluminescence activity.