Study On Preparation Of Copper Sulfide Film By Chemical Bath Deposition

Copper sulfide is a very important p-type semiconductor material.It has excellent electromagnetic and optical properties,which is widely applied in fields of solar cells,photoelectric conversion switches,gas sensitive sensors and photocatalysis.The thesis has explored a low temperature and environmental-friendly synthesis route-chemical bath deposition(CBD)to prepare copper sulfide thin films.The effects of chemical bath deposition parameters such as solution ratio,p H,concentration of solution,deposition temperature and duration on thin films have been investigated in detail.The results showed that the uniform dense Cu S thin film can be successfully obtained with a p H of 8.5 to 8.8 at 65 °C – 70 °C for 2.5 h – 3.0 h.The prepared films were composed of hexagonal nanosheets erected vertically on the substrate surface.The visible light transmission of the film is more than 35 %.The thickness of the films changed from 40 nm to 280 nm by controlling deposition parameters.It was found that the heterogeneous nucleation rate and growth rate of the film can be adjusted by p H,solution ratio and concentration.With the increase of p H from 7.0to 9.0,the thickness of the film increased from 66 nm to 150 nm,while the transmission decreased from 78 % to 50 %.With further increasing p H,the thickness of the obtained film decreased.With the decrease of the ratio of Cu2+ to C6H5O73-,the obtained films gradually thickened from 160 nm to 280 nm,while the transmission gradually decreased from 43 % to below 10 %.With the increase of the ratio of Cu2+ to S2-,the thickness gradually increased from 150 nm to 280 nm,and the transmission decreased significantly from 20 % to 3 %.When Cu2+: C6H5O73-:S2-= 1:3/2:2,the transmission decreased gradually from 50 % to 38 % as the solution concentration increased,and the films thickened up to 150 nm.With the increase of deposition temperature,the thickness increased from 50 nm to150 nm,and the thickness increased slowly at temperature range of 50?-65?,while increased significantly at range of 65?-80?.It indicated that increasing temperature can speed up the film deposition.When the temperature was exceeded 80 °C,the thickness of decreased and the transmission rate increases,which illustrated that further raising temperature will lead to consume a great quantity materials due to homogeneous nucleation.As prolonged the deposition duration,the thickness increased rapidly,and attainedconstants(about 200 nm)thereafter.The transmission decreased from 60 % for 30 min down to 38 % for 5 h.The phenomenon is consistent with the self-catalytic dynamic behavior of chemical solution deposition processing.This low-temperature,low-consumption,and environmental-friendly chemical synthesis route can be further expanded to other semiconductor film preparation research.