Fabrication Of The Amorphous Silicon Solar Cell And Numerical Modeling Of Microcrystalline Silicon Solar Cell

Recently, a lot of conventional energy resource has been used and led to many problems that climate isbecoming warm and ecological deterioration is becoming more and more serious. People pay moreattention to renewable energy sources that are clean, no-pollution. Compared with wind and nuclearenergy, the solar energy with a few advantages that are no-pollution, low-cost and no limitation to theplace has the broad prospect. The preparation technology of silicon thin film solar cells is simpler thanthat of crystal silicon solar cells. The low deposition temperature and the low cost of substrate materialmake the low cost of silicon thin film solar cells. So study on the silicon thin film solar cells is hot spot.In this paper, we focus on the silicon thin film solar cells. The paper consists of two parts. First, thesilicon thin film and a-Si:H thin film solar cell have been fabricated by PECVD. Another part is thatAMPS-1D (Analysis of Microelectronic and Photonic Structures) program developed by Pennsylvaniastate university has been carried out to simulate the performances of microcrystalline silicon solar cells.The silicon thin films were deposited on different substrates including quartz substrate and siliconsubstrate by PECVD. Transmission spectra、The Raman spectroscopy and Fourier transform infrared(FTIR) spectra of the films were tested. The relation between deposition condition and the dispositionspeed and optical bandgap of the silicon thin films was analyzed. The flow rate of SiH4and the depositiongas pressure are the most critical factors to Egof Si thin film. The flow rate of H2plays a secondary role.The effects of the plasma power and the substrate temperature are weaker. The flow rate of SiH4plays theimportant role on the disposition speed of Si thin film. Total gas pressure plays a secondary role. And theeffects of the plasma power and the substrate temperature are weaker. The flow rate of H2plays the lowestroles on the disposition speed of Si thin film. The optical bandgap of the window layers plays a crucialrole in determining the performance of amorphous silicon solar cells. The window materials with widebandgap can increase the quantity of the solar energy into intrinsic layer as much as possible and improvethe open-circuit voltage of the solar cells. The window layer of solar cells with wide optical bandgap hasbeen optimized by varying deposition gas pressure and deposition temperature. The optical bandgap ofPIN amorphous silicon solar cells is discontinuous, which leads to the discontinuous energy band at the i/pand i/n interfaces. It increases recombination rate near the interface region and reduces the electric field of i layer. Buffer layer in amorphous silicon solar cell is introduced for the purpose of improving the p/iinterface and i/n interface. The thickness of buffer layers plays an important role on performance of a-Si:Hthin film solar cell, so the thickness of buffer layer were discussed in this paper. By optimizing the p/iinterface and i/n interface, the solar cells with conversion efficiency of6.47%have been successfullyfabricated with the Vocof0.923V and a fill factor of0.667, respectively. By optimizing boronconcentration, amorphous silicon solar cells with conversion efficiency of7.1%have been successfullyfabricated with a Vocof0.917V, Jscof11.08mA/cm2and a fill factor of69.9%, respectively.Device modeling of Glass/TCO/p/i/n/Al junction microcrystalline silicon solar cells has beencarried out using AMPS-1D program developed by Pennsylvania state university in this paper. The effectsof windows layer thickness and barrier height of the front contact on the build-in potential and the p-layerbarrier height of pin microcrystalline silicon solar cell have been examined and the mechanism areanalyzed. Simulation results indicate the performance of microcrystalline silicon solar cells get betterwhen the barrier height of the front contact increases. When the barrier height of the front contact is lessthan1.30eV, the thickness of the p-layer strongly influence performance of solar cell and the bestperformance of the solar cell was achieved when windows layer thickness is12nm.