Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/3012
標題: 漸變本質層氫化非晶矽鍺薄膜太陽電池
Graded intrinsic-layer a-SiGe:H thin-film solar cells
作者: 江英銘
Chiang, Ying-Ming
關鍵字: 氫化非晶矽鍺太陽電池;a-SiGe:H;V型結構;電漿功率;漸變能隙;V-shape;RF power;graded bandgap
出版社: 光電工程研究所
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摘要: 
氫化非晶矽鍺(a-SiGe:H)薄膜由於鍺原子的摻雜而降低薄膜的光學能隙,可增加本質層薄膜對長波長光的吸收係數,但是當鍺原子摻雜越多時卻會增加薄膜內部的缺陷,導致薄膜品質的劣化。本論文使用氫稀釋與調變射頻功率使薄膜在沉積時變化氫電漿處理的強度,以降低因鍺原子的摻雜而產生的弱鍵,改善薄膜品質。

在本質層中使用漸變能隙a-SiGe:H多層膜方式增加i層內之電場強度,改善光生載子的收集。以固定本質層總厚度而調變a-SiGe:H多層膜漸變能隙的斜率,隨著斜率的變化會影響電子電洞對的產生與收集,使得短路電流密度與填充因子隨之變化。為了讓p/i介面與i/n介面之光學能隙有更佳的連接,因此加入p/i與i/n漸變緩衝層,可提高開路電壓與填充因子。

隨著a-SiGe:H本質層厚度的增加可提高更多的光吸收,以增加短路電流密度,但是會降低薄膜內部的內建電場,使填充因子大幅下降。為了改善a-SiGe:H太陽電池的光生載子收集效率而採用V型漸變能隙a-SiGe:H多層膜結構,以調變V型結構最低能隙位置改變太陽電池特性。在本研究中,所獲得到最高效率之V型漸變本質層能隙之太陽電池,其轉換效率為7.01%、短路電流密度為16.5 mA/cm2、開路電壓為0.76 V、以及填充因子為55.8%。

The optical band gap of hydrogenated amorphous silicon-germanium (a-SiGe:H) thin film is decreased with raising of doped germanium atoms, which lead to an increase in absorption coefficient at long wavelength light in intrinsic a-SiGe:H layer. However, defects of a-SiGe:H films are increased as increasing of germanium atoms result in inferior qualities of thin films. In this thesis, changing hydrogen plasma treatment by hydrogen dilution and RF power is used to reduce weak bonds due to doping of germanium atoms, thus to improve the qualities of a-SiGe:H films.
For improving collection of photogenerated carriers, graded optical bandgap multilayer a-SiGe:H film is designed to increase the build-in electric field in the film. Changing the slope of graded bandgap with fixed total thickness of a-SiGe:H intrinsic layer can influence the electron-hole pair generation and collection and the variations of electrical properties of a-SiGe:H solar cells especially on short-circuit current density and fill factor. Adding p/i and i/n graded layers can reduce the band offset at p/i and i/n interfaces, and enhance open-circuit voltage and fill factor.
As increased thickness of a-SiGe:H intrinsic layer achieve raise in light absorption, the short-circuit current density is increased. Nevertheless, the build-in electric field in a-SiGe:H film is reduced result in the decrease of fill factor. V-shape graded optical bandgap multilayer a-SiGe:H structures have been adopted to improve the collection efficiency of photogenerated carriers. Changing the lowest bandgap position of V-shape structure can alter the solar cell performance, in this study, the best performance of V-shape a-SiGe:H solar cell has the energy conversion efficiency of 7.01%、short-circuit current density of 16.5 mA/cm2、open-circuit voltage of 0.76 V、fill factor of 55.8%.
URI: http://hdl.handle.net/11455/3012
其他識別: U0005-2708201212094500
Appears in Collections:光電工程研究所

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