Papers by Keyword: Crystalline Volume Fraction

Abstract: Performance of micro-/poly-crystalline SiGe alloy solar cell of TCO/(n)a-Si:H/(i)a-Si/(p) c(pc)-SiGe/(p+)μc-Si/Al structure was analyzed via the AFORS-HET software. Cell structures can be designed to reach up to the optimal performance. Employment of back surface electric field layer of (p+)μc-Si could improve cell properties. The maximum photoelectric conversion efficiency η=21.48% occurs in a cell with average Ge percent content x0.1 and 250 m-thick Si1-xGex alloy light absorption layer, which is higher than the experimental result of the same absorption layer thickness crystalline Si HIT cell [Progress in Photovoltaics: Research and Applications, 8 (2000) 503.]. Temperature dependence of the cell performance parameters (open circuit voltage Voc, circuit current density Jsc, fill factor FF and efficiency η) indicates that Si0.9Ge0.1 cell shows weaker temperature sensitivity than that of pure Si cell. Numerical calculation illustrates that Voc decreases while Jsc, FF and η heighten with raising mean grain sizes and crystalline volume fractions, these variations with the later are more remarkable. Present optimized technique will be benefit to designing and fabricating the high performance solar cell.

Abstract: It is necessary to improve the open circuit voltage of amorphous silicon solar cells for its applications. In this paper, we discuss the effects of hydrogen plasma treatment on the P layer and the performance of the amorphous silicon solar cells. The result shows that the open circuit voltage increased by 0.0257V, the fill factor increased by 0.039 and the energy conversion efficiency increased by 9%. The highest V_OC we got was 0.99V. Treating P layer with hydrogen plasma has been demonstrated to result in materials with improved crystalline volume fraction which was very effective to increase the light absorption of the intrinsic layer. What is more, it could be easily integrated into the amorphous silicon solar cell mass production process.

Abstract: Hydrogenated nanocrystalline silicon (nc-Si:H) films were deposited on glass substrates using Radio frequency plasma-enhanced chemical vapor deposition(RF-PECVD)from a B2H6/SiH4/H2 gas mixtures. In this paper, we mainly changed the Borane-Silane flow rate ratio (β), while other parameters were kept constant. Raman spectrum and X-ray diffraction were employed to investigate the micro-structure of the films, and the indentations were used to measure the mechanical characters (the Young’s modulus (E) and hardness (H)). The Raman spectrum showed that, withβincreasing the crystalline fraction decreased, which indicated that more boron doped might not be propitious to the formation of crystalline of the thin films. XRD spectrum revealed that the films have a remarkably preferential orientation. The analysis of the Young’s modulus and hardness by TriboIndenter nano system suggested that the increase inβhad concernful effects in the decrease of E and H values, so we can control the mechanical characters of the thin films by means of changing the doped concentrations. In view of these results, it may be concluded that the use of lowβconditions might lead to growth of nc-Si:H films with high crystallinity, and as well high Young’s modulus and hardness.