| Summary: | 碩士 === 國立中興大學 === 材料科學與工程學系所 === 106 === Silicon nanowire arrays has proven to be a reliable and excellent phtoto sensing device and a catalyst for photocatalytic reaction.In particular, silicon nanowire array sensor can provide a larger reaction area better anti-reflection and hegher optical absorption capacity than thin film sensor.However, it has a week photosensing properties in near-infrared region because of its indirect bandgap and energy of 1.1eV.
Because of its low energy bandgap of (0.8~0.95eV), and forming a p-n junction. β-FeSi2 is widely used in near-infrared light detectors, LEDs (light-emittting diodes), Solar cells.
In this study,silicon nanowire arrays were prepared by nanosphere lithography and metal-assisted chemical etching. β-FeSi2/Si heterstructure nanowire arrays were fabricated by 80° glancing angle Fe deposition and reactive deposition epitaxy (RDE). The electrical,photosensing and photocatalytical β-FeSi2 /Si heterostructured nanowire array devices. the electrical were investigated.
The results show that the phase of iron silicide depend on amount of iron ,deposition temperature and annealing time. When 15 nm iron deposited on silicon nanowire array at 500 °C and subsequently annealed at 700 °C for 2 hours the β-FeSi2 phase can be obtained. The β-FeSi2 /Si heterostructured nanowire arraydevice has a higher photocurrent than silicon nanowire array device. 5 nm iron deposited sample exhibited the highest decomposition rate of methylene blue dye under visible light irradiation because its rion silicide crystals had small size and separated from each other.
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