Abstract This paper reports the synthesis of zinc oxide (ZnO) nanofibers, changing the molar concentration (M) of zinc acetate dihydrate (ZnAc) using 2-methoxyethanol and monoethanolamine. X-ray diffraction pattern reveal that ZnO thin films indicate good crystallinity at high precursor concentration. Atomic force microscopy (AFM) images show the formation of ZnO nanofibers. The optical properties changing with increasing concentration are understood from the recorded transmittance, absorbance and reflectance measurements. The band-gap narrowing (from 3.28 eV to 3.22 eV) of n-type ZnO thin films is observed through the absorption edge by an increase in molar concentration. n-ZnO/p-Si heterojunction structure exhibits low rectifying ratio ( RR ). The current-voltage ( I - V ) characteristics show that the conductivity increases as the molar concentration of precursor decreases from 0.5 to 0.2 M. An optimum value of molar percentage for precursor concentration of ZnAc is promising for photovoltaic and display applications.