Study On CdTe Targets Preparation And Coating Crafts

CdTe band gap is1.46eV, which spectral response is very consistent with sunlight spectrum, the light absorption modulus is up to10-5cm-1, the theory photoelectric conversion efficiency is29%, that is recognized as efficient and clean thin-film solar cell absorption material. With the development of CdTe thin film solar cell technology, efficient and suitable for large-area sputtering coating crafts have become the main method of preparing CdTe thin films, research institutions have done a lot of research for sputtering coating crafts at home and abroad. Sputtering targets as coating raw materials play a decisive role on film properties. For technological security, countries rarely report this production preparation technology. Therefore, the study on targets preparation techniques is very necessary which is significant for domestic CdTe targets and thin-film solar cells industry development.In this paper, vacuum melting CdTe bulk is used as raw materials, after crushing to300um, which used a ball mill grinding CdTe powder. By studying the grinding atmosphere and grinding time that impacted on CdTe powder particle size, purity, phase structure, microstructure morphology, which establishes the optimum grinding time is10h, it successfully prepares high-purity CdTe powder which particle Size is3-4um, impurity elements are less than75ppm.Designing orthogonal experiment which uses hot-pressing sintering technology preparing CdTe targets by using prepared CdTe powder as raw materials. By using Archimedes method, XRD, SEM, ICP-MS and other analytical tools that characterized CdTe targets density, phase structure, morphology, purity and other properties. Through the orthogonal experiment range analysis results, the factors affecting the density of CdTe target primary and secondary order parameters are holding time, sintering temperature, sintering pressure. Variance analysis show that changes of holding time and pressure which impact on the target density are notable, the influence of sintering temperature changes are slight. Determining the optimum parameters for hot pressing preparation technology: sintering temperature580℃, holding time60min, sintering pressure33MPa. Preparing CdTe target under optimal conditions, the target density reach99.4%, through observing target fracture surface which find grain size is uniform, the target density is well, and has minute quantity closed pores.The target density of97.7%, respectively, target density of99.4%which prepared under optimal conditions that as sputtering source which use rf magnetron sputtering. By comparing the film deposition rate, phase structure, light absorption coefficient, electrical resistivity, that find the film prepared by target density of99.4%all aspects of performances are than the film prepared by target density of97.7%. The deposited CdTe films are annealed one hour in a vacuum state at150℃,250℃,350℃Cwhich find films from amorphous structure into a face-centered cubic structure and with the annealing temperature increasing a sharp decline in film resistivity.Through this paper study which establishes a hot-pressing preparation craft of CdTe targets that prepares thin film solar cells, experiments using rf magnetron sputtering and studying films and targets properties, the results show that the targets are prepared to meet the needs of the thin film solar absorbing materials, the basis for the study of industrial production and use of materials which provide a research base for this material industrial production and use.