Time-resolved luminescence and Furje Transformation Infrared (FTIR) absorption spectroscopy for ZnO nanocrystals prepared under different chemical reactions using microwave driven hydrothermal process was studied. OH group stretching vibration frequency is considerably different in nanocrystals studied and in single ZnO crystal. It is shown that fractions of chemicals used in synthesis process could be found in nanopowders. Luminescence at similar to 2.0 eV (due to defect states in ZnO crystals and nanopowders) was suppressed in nanopowders obtained by urea method.