Optical properties Energy gap 17 Zinc oxide 13 Thin films 10 Sol-gels 8 Scanning electron microscopy 7 Density functional theory 6 II-VI semiconductors 6 III-V semiconductors 6 Infrared devices 6 Semiconductor doping 6 Sol-gel process 6 Chlorine compounds 5 Crystal structure 5 Electronic equipment 5 Electronic properties 5 Field emission microscopes 5 Optical films 5 Perovskite 5 Photoluminescence 5 Structural properties 5 Substrates 5 Thermoelectric equipment 5 Aerosol optical depths 4 Coatings 4 Copper oxides 4 Electrical properties 4 Electronic structure 4 Field emission scanning electron microscopy 4 Glass 4