摘要(英) |
In the last decades, the researches of thin film solar cells have attracted much attention for the reason of the energy crisis. Plasma-enhance chemical vapor deposition (PECVD) is the most popular method to fabricate silicon thin film solar cells. The disadvantages of PECVD are the high facility cost and using the toxic processing gases such as silane (SiH4), B2H6 and PH5. To solve the problem the reactive radio frequency sputtering deposition was applied in this research, which is a safe and cheap method to fabricate the doped hydrogenated microcrystalline silicon without using any toxic gas. The p type and n type hydrogenated microcrystalline silicon (μc-Si:H) thin films were fabricated with the different concentration of the doped target and the hydrogen gas flow. The properties of the films were measured using Alpha–Step, XRD, conductivity, carrier concentration, carrier mobility, and activation energy measurement. The results show that when the boron grains occupied 30% of the p type silicon target area and hydrogen flow 9sccm, the best conductivity is achieved at about 3.79×10-2 S/cm for the p type μc-Si:H thin film. The μc-Si:H grain size is 4.84nm in the film. The activation energy is 0.044ev. Using Hall measurement, the carrier concentration is achieved at 3.34×1018cm-3 and carrier mobility 0.516cm2/V-S. Besides, when n type silicon wafer occupied 75% of the silicon target area and hydrogen flow 7sccm for the n type μc-Si:H thin film, the best conductivity is achieved at about 9.66×10-3 S/cm. The μc-Si:H grain size is 12.5nm in the film. The activation energy is 0.11ev. Using Hall measurement, the carrier concentration is achieved at 1.11×1018cm-3 and carrier mobility 0.525cm2/V-S. Both results have met the requirements of p type and n type μc-Si:H thin films for the application of thin film solar cells. |
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