臺灣博碩士論文加值系統

The aim of this work is to develop high efficiency grating solar cell using cheap etching techniques such as electrochemical etching to produce new grating structures on silicon substrate which gives better anti-reflection effect and increase of surface areas, to promotes the light capture effect and increase the p-n junction interface area. We investigated the influence of etching parameters as well as passivation effects on photoparameters of the grating solar cell.
We observed that the pore size, depth and spacing of the grating structure are dependent on the etching conditions. With ideal etching condition, ie with etchant solution concentration of 3M HF/DMSO, current density of 5mA/cm2, and etching time of 40 minutes, the pores are found to be evenly distributed with a trench spacing of 2 μm, and depth of about 10 μm.
Passivation was carried out by using silicon dioxide films grown by HDP CVD and the high temperature furnace and found that performance of the grating solar cell having passivation with silicon dioxide film grown by HDP CVD is better than that with silicon dioxide film grown by furnace. Also surface passivation effect was very much obvious and efficiency increased from 3.1% to 8.1% after the surface passivation with silicon dioxide film grown by HDP CVD.

本研究欲發展改良型欄柵太陽能電池，結合便宜的蝕刻技術電化學蝕刻法，成功的製作出新型結構之矽基板，具優良的抗反射效果與多的表面積，應可用來當作太陽能電池基板，以提升光的捕捉效應與增加p-n介面的面積。因此，本論文主要討論蝕刻參數對基板形貌的影響。並製作出電池，討論不同基板形貌還有利用HDP CVD 及高溫爐管長成二氧化矽來比較表面鈍化對電池電性的影響。
當電化學蝕刻成長多孔矽時，可觀察到不同條件會形成不同的表面。多孔矽深溝渠結構成功的蝕刻，且分佈均勻，溝槽間距約2µm，深度決定約10µm左右，可避免高溫擴散n+射極時因間距太窄而失去p-n介面。
比較不同基板形貌對電池電性的影響，多孔矽基板製作出的太陽能電池，Jsc有明顯的上升，效率有提升的趨勢，而在經過表面鈍化後的Voc也會有明顯上升，可以此技術來製作高效率太陽能電池。

English Abstract..............................I
Chinese Abstract..............................II
Acknowledgement...............................III
Table Captions................................VI
Figure Captions...............................VII
Chapter 1 Introduction.........................1
Chapter 2 Theory and solar cell Mechanism......4
2.1 Basic theory of solar cell................4
2.2 The Physical of the Solar Cell............4
2.3 The Current-Voltage Characteristic........7
2.3.1 Short Circuit Current ..................7
2.3.2 Open Circuit Voltage....................8
2.3.3 Fill Factor.............................8
2.3.4 Efficiency..............................9
2.4 Electrical Losses.........................10
Chapter 3 Experiment flow and equipment........11
3.1 Process flow of Grating Solar cell.........11
3.1.1 Simple preparation.......................11
3.1.2 Electric chemical etching................11
3.1.3 Passivation..............................11
3.2 High-Density plasma Chemical Vapor Deposition......13
3.3 Measurement techniques.............................15
Chapter 4 Porous silicon Results and discussion.........23
4.1 Porous Si on low resistivity silicon substrate.....23
4.2 Porous Si on high resistivity silicon substrate....28
4. 3 Porous Si formation using a different etchant.....33
4. 4 Disscussion.......................................36
Chapter 5 Fabrication of grating solar cell and different passivation techniques.................................38
5.1 Fabrication of the solar cell......................38
5.2 Diffusion Furnace..................................42
5.3 Analysis of electrical characteristics and discussion.............................................43
Chapter 6 Conclusion and Future Work....................54
Reference ..............................................55

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