With the aim of developing a new silicon refining process for production of solar grade silicon, a low-temperature refining technique referred to as ＂solidification refining of silicon with a Si-Al solvent at low tem...With the aim of developing a new silicon refining process for production of solar grade silicon, a low-temperature refining technique referred to as ＂solidification refining of silicon with a Si-Al solvent at low temperature＂ was studied. The refinability of silicon by the partial solidification from a Si-Al solvent was discussed with thermodynamic evaluation for the impurity segregation between solid silicon and a Si-Al solvent. Impurity segregation ratios were measured by using temperature gradient zone melting method for phosphorus and boron and were estimated by the thermodynamic calculation for metallic impurities. The excellent refinability was clarified from the extremely small segregation ratios of impurities at lower temperature and was also confirmed by the test refining with the partial solidification under the induction heating. Furthermore, silicon crystal growth was studied by directional solidification experiments of a Si-Al alloy, and was estimated to be diffusion controlled.展开更多
Ion implantation may favorably modify the properties of polyaniline/Si heterojunction solar cells fabricated by the electrochemical method. Influences of the implantation on the absorption spectrum and the thermal sta...Ion implantation may favorably modify the properties of polyaniline/Si heterojunction solar cells fabricated by the electrochemical method. Influences of the implantation on the absorption spectrum and the thermal stability were discussed and output properties were measured. The results show that the absorption spectrum of the polyaniline films modified by ion implantation is much wider; its pyrolytic temperature increases by 40℃, and the polyaniline/Si cell efficiency increases 18 and 3 times under the illumination of （10.92） and 37.2W/m2, respectively.展开更多
The investigation of multi-crystalline silicon （mc-Si） surface etching technology is a key point in solar cell research. In this paper, mc-Si surface was etched in the common alkaline solution modified by an additiv...The investigation of multi-crystalline silicon （mc-Si） surface etching technology is a key point in solar cell research. In this paper, mc-Si surface was etched in the common alkaline solution modified by an additive for 20 minutes at 78-80~C. Samples＇ surface morphology was observed by scanning electron microscope （SEM）. It is firstly found that the etched mc-Si surface has the uniform distribution of trap pits although the morphologies of trap pits are slightly different on different crystallographic planes. Si （100） plane was covered with many small Si-mountaln ranges or long V-shape channels arranged in a crisscross pat- tern. For （110） plane and （111） plane, they were full of a lot of triangle pit-traps （or quadrilateral holes） and twisted earthworm trap pits, respectively. The measured reflectance of the sample was 20.5% at wavelength range of 400--900 nm. These results illustrate that alkaline solution modified by an additive can effectively etch out trap pits with a good trapping light effect on mc-Si surfaces. This method should be very valuable for mc-Si solar cells.展开更多
文摘With the aim of developing a new silicon refining process for production of solar grade silicon, a low-temperature refining technique referred to as ＂solidification refining of silicon with a Si-Al solvent at low temperature＂ was studied. The refinability of silicon by the partial solidification from a Si-Al solvent was discussed with thermodynamic evaluation for the impurity segregation between solid silicon and a Si-Al solvent. Impurity segregation ratios were measured by using temperature gradient zone melting method for phosphorus and boron and were estimated by the thermodynamic calculation for metallic impurities. The excellent refinability was clarified from the extremely small segregation ratios of impurities at lower temperature and was also confirmed by the test refining with the partial solidification under the induction heating. Furthermore, silicon crystal growth was studied by directional solidification experiments of a Si-Al alloy, and was estimated to be diffusion controlled.
基金Natural Science Foundation of Shaanxi Province ( 2004CS110005 ) Research Foundation of NorthwesternPolytechnical University
文摘Ion implantation may favorably modify the properties of polyaniline/Si heterojunction solar cells fabricated by the electrochemical method. Influences of the implantation on the absorption spectrum and the thermal stability were discussed and output properties were measured. The results show that the absorption spectrum of the polyaniline films modified by ion implantation is much wider; its pyrolytic temperature increases by 40℃, and the polyaniline/Si cell efficiency increases 18 and 3 times under the illumination of （10.92） and 37.2W/m2, respectively.
基金supported by the Shanghai Aerospace Foundation (Grant No. GC072003)
文摘The investigation of multi-crystalline silicon （mc-Si） surface etching technology is a key point in solar cell research. In this paper, mc-Si surface was etched in the common alkaline solution modified by an additive for 20 minutes at 78-80~C. Samples＇ surface morphology was observed by scanning electron microscope （SEM）. It is firstly found that the etched mc-Si surface has the uniform distribution of trap pits although the morphologies of trap pits are slightly different on different crystallographic planes. Si （100） plane was covered with many small Si-mountaln ranges or long V-shape channels arranged in a crisscross pat- tern. For （110） plane and （111） plane, they were full of a lot of triangle pit-traps （or quadrilateral holes） and twisted earthworm trap pits, respectively. The measured reflectance of the sample was 20.5% at wavelength range of 400--900 nm. These results illustrate that alkaline solution modified by an additive can effectively etch out trap pits with a good trapping light effect on mc-Si surfaces. This method should be very valuable for mc-Si solar cells.
