Study Of Polycrystalline Silicon Thin Film Solar Cells Prepared By Pecvd

Solar cells is one of the important solutions to solve the energy crisis, currently have monocrystalline silicon, polycrystalline silicon solar cells, monocrystalline silicon solar cell conversion efficiency has reached24%, polysilicon solar cell efficiency reached10%. These two kinds of solar cells account for the vast majority of market share. However, because of the cost of solar cells, mainly of monocrystalline silicon, polycrystalline silicon prices, lead to solar cell production cost is higher. So, people find the development direction of the thin film solar cells. The mature of amorphous silicon thin film solar cells, copper indium gallium selenide (CIGS) thin film solar cells, dye sensitized solar cells and so on. For silicon thin film solar cells, and can be classified into amorphous silicon and polycrystalline silicon thin-film batteries. Amorphous silicon thin film is mainly by using plasma enhanced chemical vapor deposition (PECVD) technique method. With silane (SH4), hydrogen (H2) as the main reaction gas, preparation of hydrogenated amorphous silicon (a-Si: H) thin films. And use of diborane (B2H6), phosphorus alkanes (PH3) of amorphous silicon doping, p-type and n-type semiconductor material. Amorphous silicon thin film solar cells long wavelengths of sunlight have better absorption coefficient, but the thickness of the thin film solar cells is generally only a few hundred nanometers, so simple p-n junction amorphous silicon thin-film batteries to light absorption rate is not high, in order to solve this problem, often using P-I-N structural design, so that we can appropriately increase intrinsic layer layer (Ⅰ) the thickness of the film, to improve the solar cell light absorption. But due to the disorder of amorphous silicon materials, carrier mobility and lifetime and diffusion length is much lower than in the single crystal silicon, so make amorphous polycrystalline silicon thin film, can reduce the composite of the carrier in the grain boundary, effectively increase the service life of carrier, so as to improve the conversion efficiency of the battery. Generally use PECVD had great difficulty in direct deposition of polysilicon thin film technique, so usually use amorphous silicon metal induced crystallization, solid phase crystallization and laser crystallization and so on.In this thesis, based on the amorphous silicon metal induced crystallization, crystallization of polycrystalline silicon thin film is then used as a kind of crystal layer, use PECVD deposition of silicon thin film technique, polycrystalline silicon thin film can be obtained directly. Main work is divided into two parts:(1) with metal induced crystallization of amorphous silicon thin film method, mainly explore the aluminum (Al) and tin (Sn) of amorphous silicon. Implements the crystallization of amorphous silicon on glass substrate. Using aluminum induced annealing treatment,2hours at500℃for thickness of about200nm crystallization of amorphous silicon thin film; Using metal tin, begins to crystallization of amorphous silicon at400℃,450℃temperature has gained high crystallization rate of polycrystalline silicon thin film. Get more practical preparation technology parameters of the crystal layer.(2) the installation and debugging lab first plasma enhannced chemical vapor deposition (PECVD) equipment, for the use of the device characteristics, preliminary preparation of hydrogenated amorphous silicon thin film (a-Si:H), the structure of thin film and photosensitivity test and analysis, to master the basic process. For the preparation of amorphous silicon and polycrystalline silicon thin film solar cells accumulated the certain method.