Preparation And Research Of High Performance P-type Conductive Transparent Tin Films And Homojunction

Tin oxide（SnO₂）is the first commercial transparent conductive oxide（TCO）thin film for its excellent electrical,magnetic,optical,gas sensing and other characteristics.And it also has an important application prospect in high temperature electronic devices,transparent electronics and shortwave light emitting devices.However,for most commercial applications in related electronic devices,the transparent conductive thin films primarily rely on n-type TCOs,but with little matching p-type TCOs.If p-type TCOs possess good optical and electrical properties,then they can be applied to active devices,such as transparent p-n junctions,field effect transistors and even transparent integrated circuits.Based on the present research status,this paper combined theory and previous research experience in Sb doped SnO₂（ATO）thin films and successfully fabricated the high performance p-type SnO₂:Sb thin films.In this paper,we fabricated ATO thin films on both quartz glass and soda-lime glass substrates by radio frequency（RF）-magnetron sputtering using high performance ATO ceramic targets with defferent Sb doping level,which were sintered by a spark plasma sintering furnace.And then,we study the effect of substrate,Sb doping level,heat treatment system,film thickness and diffusion barrier layer on crystalline structure,microstructure,chemical state,conductivity type,optical and electrical properties and so on.Experimental study found that Sb doping concentration had a great influence on the conductivity type of SnO₂ thin films.When Sb doping level was≤5 at.%,ATO thin films showed n-type conductivity.The conduction type for 10 at.%Sb-doped SnO₂ thin films transformed from p-type to n-type at the annealing temperature of500℃.However,20 at.%Sb-doped SnO₂ thin films deposited on quartz glass with the thickness of about 450 nm showed p-type conductivity atalmost annealing temperature.When it annealed at 650℃,which possessed the lowest resistivity,that was 1.076×10²²cm^-3,1.025×10^-1 cm²·V^-1·s^-1 and 5.660×10^-3?·cm,respectively.When it was annealed at 700℃,then the highest optical average transmittance of 85.9%was obtained.ATO thin films deposited on soda-lime glass all showed p-type conductivity and the highest conductivity was obtained with the carrier concentration,Hall mobility,resistivity and average optical transmittance of 8.562×10²¹ cm^-3,9.939×10^-2cm²·V^-1·s^-1,7.335×10^-3?·cm and 86.4%,resistivity,at the optimum Si layer thickness of 80 nm and the annealing temperature of 550℃.Based on the p-type ATO thin films with optimum photoelectric performance,then fabricated SnO₂-based p-n（p-ATO（20 at.%Sb）/n-ATO（5 at.%Sb））homojunction on quartz glass and soda-lime glass,respectively,which showed good rectifying property.However,large reverse leakage surrent and small forward surrent exhibited by such homojunction for the mismatched electrical performance parameters of p-type and n-type ATO thin films,which still need further experimental analysis.