| Compared with the traditional crystalline silicon solar cells with complex structure and doping process,the AZO/CdS/Si crystalline silicon heterojunction solar cells have the advantages of simple structure,few procedures and low cost.The AZO/CdS/Si heterojunction solar cells were fabricated by magnetron sputtering.The effect of preparation of back electrodes on the solar cells performance was explored.The structure and morphology of CdS layer at different sputtering power,sputtering pressure and sputtering time were studied in detail.The effects of CdS layer on the quantum efficiency and performance parameters of the batteries were also studied.Finally,the optimal preparation conditions of various aspects were integrated to optimize the solar cell.The research results are as follows:1.The solar cell with an Ag back electrode deposition rate of 4.83?/s was superior to the solar cell with an Ag back electrode deposition rate of 9.52?/s.2.After analyzing the influence of different preparation conditions of CdS layer on the structure and morphology of CdS thin film and the quantum efficiency and performance parameters of the solar cell,the following conclusions were obtained:1)In the study of sputtering power of CdS thin films,the higher the sputtering power was,the faster the growth rate of the films increased and the thicker the thickness of films was.The different sputtering power had little effect on the preferential orientation of the hexagonal(102)peak of CdS films.When the sputtering power was 50 W,the CdS thin film had a large and uniform grain size,showing a flat and dense morphology,and the film had the best quality.At this sputtering power,the solar cell had maximum parallel resistance and a minor series resistance,and the solar cell had the highest quantum efficiency and photoelectric conversion efficiency of 3.95%.2)In the study of sputtering pressure of CdS thin films,the higher the sputtering pressure was,the faster the growth rate of the films decreases and the thinner the thickness of the films was.The different sputtering pressure had little effect on the preferential orientation of the hexagonal(102)peak of CdS films.When the sputtering pressure was 0.35 Pa,the CdS film had the largest grain size,the smallest number of holes,and the best film quality.At this sputtering pressure,the solar cell had maximum parallel resistance and minimum series resistance,and the solar cell had the highest quantum efficiency and photoelectric conversion efficiency of 4.45%.3)In the study of sputtering time of CdS thin films,the sputtering time had little effect on the growth rate of CdS film.When the sputtering time was 30 min and the film thickness was 50 nm,the defects of the CdS film were less,and the solar cell had the highest quantum efficiency and photoelectric conversion efficiency of 4.29%.3.The optimal preparation process was summarized in these aspects:the Ag back electrode was deposited at 4.83?/s,and the CdS layer with 50 nm thickness was deposited at 50 W sputtering power and 0.35 Pa sputtering pressure.Finally,a solar cell with an efficiency of 6.82%was fabricated.The parameters of the solar cell were:the open circuit voltage was 487.7 mV,the density of short-circuit current was 27.29 mA/cm~2 and the fill factor was 51.26%.A preliminary exploration and research on AZO/CdS/Si heterojunction solar cells was carried out.In the next step of optimization,the interface contact between layers was improved by passivating the surface of silicon wafer and adding a buffer layer to further optimize the performance of the cells. |
