| Summary: | 碩士 === 國立臺灣大學 === 光電工程學研究所 === 100 === The influence of nanostructure on the propagation of optical waves within amorphous thin-film silicon solar cells was investigated. Also, the influence of the amorphous silicon thin film (500 nm thick) with periodic gratings formed by array of nanowires with varied heights and different shaped profile on the conversion efficiency was studied via simulation for its solar energy absorption characteristics. The Finite Element Method (FEM) was used to rigorously solve the Maxwell’s equations in two dimensions. By studying the influence of the duty ratio, height and period of the nanowires of the gratings and the shapes of the grating profile including tented, triangular and concave shapes, the designs of the structures were optimized to achieve higher conversion efficiencies.
Enhancement of the conversion efficiency in the blue and green wavelengths of the spectrum is achieved by using small duty ratios and periods of shaped profiles owing to its anti-reflection property, whereas the conversion efficiency in the red and infrared wavelengths of the spectrum is mainly improved by properly designed periods (P = 500 – 900 nm) and larger angles of the shaped profiles to guide light into the structures.
The enhancement of conversion efficiency both occurs when no matter what polarization of the incident wave is. The conversion efficiency of solar cells covered with triangular nanowire grating profile, which is approximately optimum, can be increased by 58.21%, 42.45%, and 20.38% compared to the cases for flat solar cells without nanowires, with nanowires, and periodic triangular textures, respectively.
|
|---|
