Journal of New Technology and Materials
Volume 8, Numéro 1, Pages 31-36
Undoped and heavily indium doped ZnO were deposited by dip-coating sol-gel method on glass substrates. When undoped ZnO was deposited the maximum value of transmittance decreases from 91% for bare substrate to less than 86%. However for ZnO:In coated substrate an unexpected high transmittance of 93.5% was obtained, exceeding that of bare glass substrate. To understand this particular behavior a theoretical model based on the propagation of electromagnetic waves in thin films was adapted to the studied samples and the measured transmittance spectra were perfectly fitted. The optical analysis of the two types of samples showed that the deposited films are dense inside the film while their refractive index decreases for the surface layers. Besides, it was noted that even if the preparation conditions are strictly identical, the heavily doped ZnO films is thicker and less dense then that of undoped ZnO. These results agree with AFM and SEM observations. The particular optical behavior described in this paper could be very beneficial for optical, optoelectronic and solar applications.
ZnO:In; transmittance; simulation; nanostructure
M. F. Harkat.