Preparation Of Al/Ga Doped SnO₂ Thin Films And The Study Of Optical And Electrical Properties

With the rapid development of smart phones,flat-panel displays,large-size flat-panel displays,and solar cells.The application of transparent conductive oxide?TCO?thin film has been attracted more attention.TCO is a functional material that combines electrical conductivity and light transmittance.Currently,TCO material has been widely used in everywhere.Among TCOs,the indium tin oxide?ITO?is the dominant TCO material for commercial applications.However,indium resources are scarce and toxic.Therefore,it is urgent to develop new TCO materials to replace indium tin oxide?ITO?.Al-doped SnO₂ and Ga-doped SnO₂ thin solid films were prepared by High Target Utilisation Sputtering deposition?HiTUS?technology on glass and silicon substrates followed by a simple annealing process.Compared with the traditional sputtering technology,HiTUS possesses the following advantages:high deposition rate at low sputtering power,high targets utilization,and low energy intensity,etc.Our work mainly focused on the effect of oxygen flow and annealing temperature on the structural,optical and electrical properties of ATO and GTO thin films.The structural,optical,and electrical characteristics of the thin films were characterized.The phase structure of the thin films was detected by XRD.The film composition were detected by EDS loaded on a scanning electron microscope?SEM?.XPS?X-ray photoelectron spectroscopy?was used to detect samples'chemical state of thin films.Hall?Hall 8400?system was used to test the electrical properties of film samples and UV-Vis?Ultraviolet-visible spectroscopy?was used to test the optical performance of the samples.The main conclusion was summarized as follows:1.Al-doped SnO₂ thin films?1?The variation of crystal structure of ATO was determined by the annealing temperature.Amorphous structure is dominant in all the as-deposit thin films.When the annealing temperature was low,amorphous structure is still in there.However,when the annealing temperature was above 250?,amorphous disappeared and the phase structure is crystal.?2?With the increase of the oxygen flow rate,the light transmittance of ATO thin films has an increase trend obviously.When the oxygen flow exceeds 3.3 sccm,the average optical transmittance of ATO thin film sample is over 80%,which meets the commercial requirements for the optical performance of TCO materials.?3?The electrical properties were determined by the O₂ flow rates and annealing temperature.When oxygen is 3.3 sccm,ATO thin film has a minimum square resistance 12.9?/sq and smallest resistivity1.3×10^-4?.cm,corresponding to the highest mobility and carrier concentration 8.2 cm2/V?s and 5×10²11 1/cm3respectively.2.Ga-doped SnO₂ thin films?1?The crystal structures of GTO thin films were not affect by the O₂ flow rates and deposition time.All the as-deposited films are amorphous at room temperature.The heat treatment can transform the crystal structures of GTO thin films.?2?With the increase of the oxygen flow rate,the light transmittance of GTO thin films has an increase trend obviously.When the oxygen flow exceeds 4.8 sccm,the average optical transmittance of GTO thin film sample is over 80%as well,which meet commercial requirements for the optical performance of transparent conductive film materials.?3?The electrical properties were determined by the O₂ flow rates.When oxygen is 4.8 sccm,GTO thin film has a minimum square resistance 33.9?/sq and smallest resistivity 3.05×10^-3??cm,corresponding to the highest mobility?14.9 cm2/V?s?and carrier concentration(37×10^-20/cm3).