Method and device for preparing polysilicon thin-film solar battery

Abstract

The invention provides a method for preparing polycrystalline silicon thin-film solar cell and a device thereof. The method comprises the steps of providing a substrate; depositing a front electrode and conducting etching on the substrate; depositing a non-crystalline silicon film on the front electrode; irradiating the non-crystalline silicon film to allow the non-crystalline silicon film to reach the melting point temperature thereof until the non-crystalline silicon film is melted to formed a molten layer with a certain depth; reducing the temperature difference between the non-crystalline silicon film and the substrate when the non-crystalline silicon film crystallizes, so as to obtain a polycrystalline silicon film with larger crystal grains; etching the polycrystalline silicon film; depositing a back electrode on the polycrystalline silicon film; etching the polycrystalline silicon film and the back electrode; and packaging the substrate, the front electrode, the polycrystalline silicon film and the back electrode to obtain a solar cell. The obtained solar cell by using the inventive method has low cost and high photoelectric transformation efficiency.

Description

technical field [0001] The invention relates to a method and a device for preparing polycrystalline silicon thin film solar cells. Background technique [0002] Polycrystalline silicon wafers and monocrystalline silicon wafers are currently the dominant materials for solar cells. Polycrystalline silicon is composed of silicon crystal grains and grain boundaries. The transport properties of carriers in silicon grains are similar to those in single crystal silicon. Carriers are only scattered more at the grain boundaries. . In polysilicon, the mobility of electrons can reach ~300cm 2 / Vs, the hole mobility can reach ~50cm 2 / Vs, which is much higher than that in amorphous silicon. For comparison between amorphous silicon and polycrystalline silicon, please refer to the attached figure 1 . In addition, the defects in polysilicon are mainly concentrated near the grain boundaries, and the probability of carriers being trapped only near the grain boundaries is high. Therefor...

AI Technical Summary

Problems solved by technology

Due to the limitation of the higher defect state density (~10 16 cm -3 ) and low carrier mobility (less than ~1cm 2 / Vs), photogenerated carriers are very easy to recombine, and the photoelectric conversion efficiency of amorphous silicon thin film solar cells and amorphous silicon / microcrystalline silicon stacked solar cells is very low, the former is only ~6%, and the latter is only ~8%.

These essential problems make it difficult to further improve the efficiency of amorphous silicon thin film solar cells

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