Mg, F co-doped zinc oxide thin films deposited by RF magnetron sputtering and their applicationto silicon thin film solar cells
| Autor: | Mao-Shan Chen, 陳茂杉 |
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| Rok vydání: | 2018 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 106 ZnO-based transparent conducting thin films prepared by radio frequency (RF) magnetron sputtering have been widely used in various optoelectronic devices. In this study, a magnesium-fluorine co-doped zinc oxide film (MFZO) and a fluorine-doped zinc oxide film (FZO) were deposited on glass substrates by a RF magnetron sputtering system. The sputtering targets are with zinc oxide targets containing 3 mol% of MgF2 and ZnF2, respectively. Effects of substrate temperature, rapid thermal annealing (RTA) temperature and time were investigated on structural, surface morphological, electrical, optical, and composition properties of those films. Hydrogenated amorphous silicon thin films solar cells (α-Si:H SCs) were prepared by plasma enhanced chemical vapor deposition to investigate the influence of the TCO films on efficiency of the solar cells. When the substrates temperature varied from room temperature to 200 ℃, the MFZO and FZO films had an optimum resistivity of 1.18×10-3 Ω-cm and 8.57×10-4 Ω-cm at a substrate temperature of 200 ℃, respectively, and the optical band gap were 3.803 eV and 3.790 eV, respectively. After RTA treatment at temperatures of 300 to 500 ℃ and at times of 15 to 120 s, MFZO and FZO films had optimum resistivities of 1.30×10-3 Ω-cm and 7.96×10-4 Ω-cm, respectively, at an RTA temperature of 400 ℃ for 30 s. The average transmittance in the visible region were both about 93%, the optical band gaps were 3.812 eV and 3.831 eV, respectively, and the FOM were 1.18×10-2 Ω-1 and 1.99×10-2 Ω-1, respectively. These films deposited at room temperature were etched through dilute hydrochloric acid concentration of 0.5% to 0.7%, and the optimum FOM was obtained at 0.5%. The average haze ratio of the etched MFZO and etched FZO films at a substrate temperature of 200 ℃ in the visible region is 55.1% and 42.3%, respectively. As to the p-i-n α-Si:H SCs prepared on the etched MFZO film, the short-circuit current density, the open circuit voltage, the fill factor, and the efficiency were 7.281 mA/cm2, 0.882 V, 68.77%, and 4.418%, respectively. Compared with the unetched MFZO electrode, it can increase the solar cells 12% short-circuit current density, 13.7% fill factor, 3.1% open circuit voltage and 34.1% efficiency. However, α-Si:H SCs prepared on the etched FZO film achieved the short-circuit current density, the open circuit voltage, the fill factor, and the efficiency of 7.217 mA / cm2, 0.869 V, 64.55%, and 4.05%, respectively. We conclude that α-Si:H SCs with the MFZO front electrode have better performance than those with the FZO one. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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