Lanthanide silicates, layered

Simple silica matrices To further illustrate the limit of this chapter, we briefly discuss one type of materials that will not be systematically reviewed layered lanthanide silicates obtained by hydrothermal synthesis. An alkaline solution of sodium silicate and lanthanide chlorides was stirred to produce a gel which was subsequently put into an autoclave under pressure at 230 °C during seven days, a procedure during which lamellar photoluminescent silicates... 

It was found that it is possible to obtain uniform, ultrathin, dielectric films down to <5 nm in thickness, by spin coating dilute solutions (0.01-0.075 M) and by applying a moderate number of layers (3 or 4). Typical dielectric constants were around 20 for most of the materials studied. The formation of interfacial silicates on Si substrates during high-temperature anneals (above 800 °C typically) with, for example, lanthanides and alkaline earth metal ions is held responsible for lowering of the effective dielectric constant of the... 

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