Sol-gels 59 Sol-gel process 38 Technology: general issues 32 Thin films 24 History of engineering and technology 22 Research & information: general 18 Titanium dioxide 16 Chemistry 14 Zinc oxide 14 Sol-gel spin coating 12 Thermoelectric equipment 11 Electronic equipment 10 Coatings 9 Energy gap 9 Nanoparticles 8 Optical properties 8 Substrates 8 Titanium oxides 8 X ray diffraction 8 Field emission microscopes 7 Field emission scanning electron microscopy 7 Materials science 7 Research and information: general 7 Silica 7 Manufacture 6 Oxide films 6 Scanning electron microscopy 6 Sol-gel spin coating method 6 Annealing 5 Atomic force microscopy 5