| Summary: | 碩士 === 國防大學理工學院 === 電子工程碩士班 === 101 === This research is using nano metal materials features, different nanoparticles have different optical, electrical, and magnetic properties by change their size finding suitable property to improve the photoelectric conversion efficiency of solar cells. By using metal’s nanoparticles,which can rough the surface and have surface plasmons to enhance the absorption of a specific wavelength, for example, increasing the violet to infrared responsivity and reduce the reflection of the incident light, this experiment was divided into three parts, first of all, the silver thin films were prepared on a silicon substrate by thermal evaporator and then through a high-temperature annealing to form nanoparticles. In our experiment, we used α-step to measure thin film’s thickness, beside that, we analyzed surface morphology and optical property by scanning electron microscopy(SEM) and UV/VIS Spectrometer. Second, we used photolithography to fabricate interdigital finger shape electrode and deposited Ni/Au to form Ohmic contact by E-beam evaporator and thermal evaporator. Fabricate silver nanoparticles on silicon substrate measuring it’s photocurrent and dark current I-V curve by solar simulation system, this system is used Xe lamp as light source. Finally, preparation nanoparticles on the fabricated solar cell, and measurement the photoelectric conversion efficiency of the solar simulator.
From our experiment, we deposited different thickness 15.2nm、25.6nm and 40.7nm sliver thin film. After annealing 20 minutes in 400℃ can form 60~70nm、80~90nm and 120~200nm different diameter nanoparticles. By UV / Vis spectrometer measured reflectivity, it can be decrease from 44.852% to 34.045%, 21.997% even 18.777% , that means silver nanoparticles can increase photo absorption efficiency. Following we fabricated same nanoparticles upon interdigital electrode finding that the photocurrent would increase 1.913,1.78,1.114 times, we also found the solar cell with/without nanoparticles it’s photoelectric conversion efficiency increase1.419%, 1.185%, 0.212%。
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