The Preparation And Properties Of Microcrystalline Silicon Films

The development and utilization of solar energy has become a global concern recently, silicon-based solar cells is widely used for photovoltaic conversion devices. There has been an increasing interest in silicon-based thin film solar cells due to the lower consumption of raw materials and the lower cost. As the key material for silicon thin film solar cells, the deposition of microcrystalline silicon thin film with high absorption coefficient and low defect density at low deposition temperature is the research focus.In this thesis, we studied the effects of Ar flow and SiH4/H2 dilution ratio on the microstructure, optical and electrical properties of the prepared microcrystalline silicon thin film during the plasma enhanced chemical vapor deposition (PECVD) preparation process. Research has found that:(1) The addition of Ar in dilution gas can effectively improve the deposition rate and the crystallization rate, which is mainly because that the addition of Ar can enhance the decomposition of the source gases, furthermore, the formed excited states Ar* can provide energy for the crystallization of precursors in growth area during their retreating inspire process. In addition, the addition of Ar in dilution gas can reduce the bombardment of the H+, which will result in the widening of the optical band gap as well as the increasing of the defect mode for the prepared microcrystalline silicon thin film; (2) The absorption coefficient and dark conductance of the film decreased with the increasing of the Ar flow, conductivity activation energy of the film were increase with the increasing of the Ar flow or the decreasing of the SiH4/H2 dilution ratio, this is due to the increasing of defect mode can reduce the Fermi energy; (3) An new approach to fabricate nanomaterial arrays has been explored:using Electrospinning network as a template, chemical etching to fabricate nano-silicon array thin film for solar cell materials.