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http://ptsldigitalv2.ukm.my:8080/jspui/handle/123456789/519664| Title: | High efficiency thin film amorphous and microcrystalline silicon solar cells : modeling, fabrication and characterization |
| Authors: | Mohammed Ikbal Kabir (P42559) |
| Supervisor: | Nowshad Amin, Prof. Dr. |
| Keywords: | AMPS-1D Solar cell Photonic structures Simulator Universiti Kebangsaan Malaysia -- Dissertations |
| Issue Date: | 9-Jan-2012 |
| Description: | The conversion efficiency of a solar cell can substantially be increased by improved material properties and associated designs. This study has adopted AMPS-1D (Analysis of Microelectronic and Photonic Structures) simulation technique to design and optimize the cell parameters prior to fabrication. Solar cells such as single and multi-junction cells based on hydrogenated amorphous (a-Si:H) and microcrystalline silicon (µc-Si:H) are analyzed by using AMPS-1D simulator. The investigation has been made based on important model parameters such as thickness, doping concentrations, bandgap and operating temperature. The efficiency of single junction a-SiO:H, a-Si:H, and µc-Si:H solar cells have been found to be 19.73%, 19.62% and 12.30%, respectively after parametric optimization. The temperature gradient found for a-SiO:H and a-Si:H have been -0.18%/o C and -0.23%/o C, respectively, which finds a-SiO:H to be more stable than a-Si:H at higher operating temperature. These optimized structures of a-SiO:H, a-Si:H and µc-Si:H based solar cells have been used as the top, middle and bottom cell to design multijunction a-SiO:H/a-Si:H/µc-Si:H solar cell that achieved the highest efficiency of 21.07% with the lowest temperature gradient of -0.17%/o C. The numerically designed and optimized a-SiC:H/a-SiC:Hbuffer/a-Si:H/a-Si:H solar cells have been fabricated by using PECVD (plasma enhanced chemical vapor deposition) where the best initial conversion efficiency of 10.02% has been achieved (Voc= 0.88 V, Jsc= 15.57 mA/cm2 and FF= 0.73) as one of the highest recorded results to date. The quantum efficiency (QE) characteristic shows the cell's better spectral response in the wavelength range of 400 nm-650 nm, which proves it to be a potential candidate as the middle cell in an a-SiO:H/a-Si:H/µc-Si:H structure. Moreover, various amorphous silicon (a-Si) layers have been deposited by Physical Vapor Deposition (PVD) i.e. sputtering technique for fabrication cost minimization. These thin films have been characterized by X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), Hall Effect Measurement, Ultraviolet-Visible (UV/Vis/NIR) and Fourier Transform Infrared (FTIR) Spectroscopy. AFM results showed the roughness RMS value for p, i, n and pin layers as 4.22 nm, 4.25 nm, 2.41 nm and 2.88 nm, respectively which find the film quality to be acceptable for high efficiency cells. The growth pattern as found in XRD indicates that the films are amorphous in nature. SEM results find that grain sizes of few films are larger and better in quality. The other investigations from Hall Effect Measurement, UV/Vis/NIR and FTIR spectrum show optimistic results for the deposition of high-quality a-Si films by sputtering technique. However, the sputtering system has not been facilitated with hydrogen for the passivation of dangling bond of amorphous silicon (a-Si) to make it hydrogenated (a-Si:H) for instance. Nevertheless, the complete cell fabrication by low cost sputtering deposition process could open the window as the potential future prospect of the study.,Certification of Master's/Doctoral Thesis" is not available |
| Pages: | 155 |
| Call Number: | TK2960.K335 2012 tesis 3 |
| Publisher: | UKM, Bangi |
| Appears in Collections: | Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina |
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