Photovoltaic characteristics of crystalline Se based Schottky junction solar cells
| Autor: | Lin, Yi-Jie, 林以婕 |
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| Rok vydání: | 2018 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 106 In the study, we fabricated crystalline Se (c-Se) based Schottky junction solar cells using tin-doped indium oxide (ITO) and Pt as the electrodes. The c-Se absorber layer was phase-transformed from evaporation-deposited amorphous Se (a-Se) by thermal annealing at 200oC in atmosphere. To improve the photoconversion efficiency, a ZnO thin film was sputter-deposited on the ITO electrode as an electron transport layer (ETL). A tellurium seed layer was required to be deposited on the ZnO layer or the ITO electrode to increase the adhesion between the c-Se and the substrate. The photovoltaic performance of the solar cell is closely related to the thermal annealing condition for conversion of c-Se from a-Se. Grains in the c-Se film increase in size with the annealing time. The photoconversion efficiency of the cell can be improved with increasing the grain size; this may be ascribed to the decrease in the grain boundaries, reducing recombination of photogenerated carriers. Thermal treatment of the ZnO ETL is also important to the photovoltaic property of the c-Se solar cell. For the cell with a-Se annealed at 200°C for 1 min, the ZnO ETL can improve the photocurrent density and the fill factor (FF) after thermal anneal at 300oC for 1 h. However, for the cell with a-Se thermally annealed at 200°C for 30 min, the ZnO ETL without the thermal annealing exhibits a relatively high conversion efficiency (3.72%) with the open circuit voltage (Voc) of 0.71 V, short circuit current density (Jsc) of 9.67 mA/cm2 and a FF of 0.542. The improvement can be understood by a higher electron concentration of the unannealed ZnO layer. The study shows that optimization of the microstructure of the c-Se absorber layer by proper thermal annealing treatments and the introduction of an electron transport layers can greatly improve the photovoltaic performance of the c-Se based Schottky solar cells. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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