NOVELTY - A gradient-temperature grown zinc oxide film is a boron-doped zinc oxide transparent conductive film formed by metal-organic chemical gas phase deposition on polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) as a flexible substrate, using diethylzinc and water as a source material, and hydrogen-diluted diborane as a doping gas. During the process, a zinc oxide film is grown at 120-130 degrees C and a suede zinc oxide film is grown at 135-155 degrees C. The total thickness of zinc oxide film is 800-1500 nm.    USE - Gradient-temperature grown zinc oxide film is used in PIN type amorphous-silicon thin film solar cell and amorphous silicon/amorphous silicon laminated film solar cell (all claimed).    ADVANTAGE - The interface characteristics between substrate and zinc oxide film are improved by the gradient-temperature growth technology. The substrate is economical, and has high transmissivity. The zinc oxide film has suede structure, favorable light scattering property and high photoelectric conversion efficiency.    DETAILED DESCRIPTION - A gradient-temperature grown zinc oxide film with flexible substrate suede structure, is a boron-doped zinc oxide transparent conductive film formed by metal-organic chemical gas phase deposition on polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) as a flexible substrate, using diethylzinc with purity of 99.995% and water as a source material, and hydrogen-diluted diborane with concentration of 1% as a doping gas. The flow of doping gas is 0.1-1%. During the process, a zinc oxide film is grown at 120-130 degrees C and a suede zinc oxide film is grown at 135-155 degrees C. The obtained boron-doped zinc oxide transparent conductive film structure includes flexible substrate/low temperature grown zinc oxide film/normal temperature grown suede zinc oxide film. The total thickness of zinc oxide film is 800-1500 nm. The reaction pressure for forming coating film is 50-600 Pa. An INDEPENDENT CLAIM is included for the preparation device of the gradient-temperature grown zinc oxide film, which has a gas transfer pipeline comprising an argon gas carrying water pipeline, an argon gas carrying diethylzinc pipeline and diborane doping gas pipeline. The argon gas carrying water pipeline is used to carry raw material water from a water storage tank. The argon gas carrying diethylzinc pipeline is used to carry raw material diethylzinc from a diethylzinc storage tank. The three pipelines are respectively provided with an air-operated valve and a flow controller. The argon gas carrying water pipeline and the argon gas carrying diethylzinc pipeline are respectively provided with a pressure gauge and a needle valve. The device has a vacuum coating chamber provided with a substrate, a heater and a gas mixing box. The raw material gas and the doping gas are transferred into the gas mixing box through the gas transfer pipeline and the gas mixing box is provided with screening holes, through which the mixed gas is sprayed on the substrate. The vacuum coating chamber is vacuumized by a vacuum pump.