The Effects Of Process Parameters To The Properties Of SnO₂ And FTO Films By Magnetron Sputtering

The electrical and optical properties of SnO₂ and FTO films prepared by sputtering are closely related to the substrate temperature and O₂ flow rate,but the effect of these two parameters is not clearly clarified in previous investigations.In this study,the SnO₂ and FTO films were deposited on glass or PET substrate by reactive RF magnetron sputtering using Sn or Sn+15wt%SnF₂ target at different substrate temperature.At each substrate temperature,the structural,electrical and optical properties of the films were investigated as a function of O₂ flow rate by X-ray diffraction?XRD?,atomic force microscope?AFM?,Hall effect,transmittance spectra and photoluminescence?PL?spectra.The results are as follows.With the increase of substarte temperature from room temperature?RT?to 300?,the cystallinity of SnO₂ and FTO films become better.At higher substrate temperature,even if O₂ flow rate is lower,cystalline SnO₂ and FTO films are still formed.When substrate temperature range from RT to 100?,FTO films deposited on PET substrate are amorphous.At fixed substrate temperature,with the increase of O₂ flow rate,the preferred orientations of SnO₂ and FTO films turn from?101?to?200?,showing F doping have little effects on the preferred orientations of films.At every substrate temperature,there exsists an optimized O₂ flow rate range to deposited films with excellent opitical and electrical properties.Better conductive and higher transparent SnO₂ films and FTO films on glass substrate can be obtained at RT and150?,respectively.In which,the lowest resistivity and corresponding transmittance of the SnO₂ films are 3.65×10^-3?·cm and 81.50%,respectively.While the lowest resistivity and corresponding transmittance of the FTO films is 2.26×10^-3?·cm and 86.43%,respectively.The lowest resistivity and corresponding transmittance of the FTO films deposited on the PET substrate at 100?is 4.28×10^-3?·cm and 85.20%,respectively.With the increase of O₂ flow rate,energy gap?E_g?of SnO₂ and FTO films on two substare sharply increase at first,and then tend to constant.The constant value increases as substrate temperature increases.As for the SnO₂ and FTO films,all the shapes of PL spectra are similar,which indicate F doping have no influence on the origins of emission feaks.The variations of emission feaks intensity related on oxygen vacancy?V_O?and carrier concentration as a function of O₂ flow rate are similar.It shows both of the electrical properties of SnO₂ and FTO films depend on V_O.