NOVELTY - Preparing cadmium sulfide film with chemical water bath method involves cleaning substrate and blowing/drying; forming reaction container using substrate and clamp; preparing solution (2) by mixing cadmium salt, ammonia water, buffer agent, thiourea and deionized water; placing container filled with reaction solution in constant-temperature water bath container (3), heating solution to 50-90 degrees C until cadmium sulfide film has required film thickness; taking off substrate deposited with cadmium sulfide film, placing substrate in deionized water to clean/wash with ultrasonic wave.    USE - For preparing cadmium sulfide film with chemical water bath method (claimed) used in solar energy battery producing technology field.    ADVANTAGE - The method saves the reaction raw materials. The single surface of the substrate is only coated, so the method improves the aesthetic extent. The deposited cadmium sulfide film is continuous, even and compact; and the method improves the film forming quality. The substrate and clamp together form a reaction container, which saves the reaction raw material, only the plating film on the substrate, improves the beauty of coating substrate, improves the quality of the product, so that in the reaction process by ultrasonic assisted deposition reduces bubble adsorption in the form of the surface of the substrate, on the other hand it reduces the large particle in the solution reaction product adsorbed on the surface of the film, so that the deposition cadmium sulfide film is continuous and uniform and compact by external water pump assisted deposition, promotes the homogenization of the reaction solution, at the same time, because the water flow scouring effect reduces the large particles absorb to the surface of the film, so as to further improve the uniformity and compactness of the cadmium sulfide film by external filtering device, the filtering of the large particles in the reaction solution, reduces the possibility of absorbed on the surface of the film, and improves the film quality.    DETAILED DESCRIPTION - Preparing cadmium sulfide film with chemical water bath method involves 1) cleaning the substrate and blowing or drying; 2) installing the substrate: placing the substrate into the special clamp to clamp firmly, interlaying the sealing ring and the rubber ring between the substrate and the clamp, and maintaining the even force and excellent seal on the four sides of the substrate, where the upper part of the clamp is formed with a water infusing opening and a water outlet respectively, where the substrate and the clamp form a reaction container; 3) preparing solution (2): mixing the cadmium salt, ammonia water, buffer agent, thiourea and deionized water according to a certain proportion to produce the reaction solution, and blending the reaction solution into the reaction kettle, where the cadmium salt is one of cadmium sulfate, cadmium acetate, cadmium chloride and cadmium iodide; the concentration of Cd2+ produced by the cadmium salt in the reaction solution is 1-10 mM; the ammonia water concentration is 0.1-1 M; the ammonium salt is one of ammonium chloride, ammonium sulfate and ammonium acetate; the concentration of NH4+ produced by the ammonium salt in the reaction solution is 0-100 mM; the concentration of the thiourea is 5-150 mM, and the other is deionized water; 4) reacting and depositing: placing the reaction container filled with the reaction solution in the constant-temperature water bath container (3), heating the reaction solution to 50-90 degrees C until the cadmium sulfide film has the required film thickness, and finishing the reaction, where the total reaction time is 5-60 minutes; and 5) subsequently processing: taking off the substrate deposited with the cadmium sulfide film, placing the substrate in the deionized water to clean or wash with ultrasonic wave, and blowing or drying.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic diagram of the cadmium sulfide thin film deposition apparatus.    Reaction solution (2)    Constant temperature water bath container (3)    Transducer (4)    External water pump (5)    Circulating flow (6)    Filtering device (7)