隨著科技的日新月益，能源的開發已成為刻不容緩的問題，其中太陽能具有無汙染、取之不竭的特性，已成為大家最關注的能源之一。但傳統的PIN結構太陽能電池，P層對短波長光不敏感，且在p/i層接面處常有大量電子電洞對的復合情形產生，因而降低轉換效率。此外製程複雜，導致成本無法降低。本論文提出一種新的太陽能電池結構TiO2/nc-Si/α-Si/ITO/glass來克服上述的缺點，本結構利用二氧化鈦薄膜(TiO2)對UV光的吸收特性，來提高元件對太陽光的吸收頻譜範圍，並以其高能隙(Eg>3.0eV)的特性來降低電子電洞對複合的機會，再利用奈米矽微小晶粒在表面形成texture結構，此結構能使陽光在TiO2/Al及TiO2/nc-Si接面處形成散射，因而增加光子在主動層內被吸收的機率。
吾人先採用電漿助長化學氣相沉積系統(PECVD)在ITO玻璃上成長非晶矽薄膜，並在相同溫度下，以疊層技術(LBL)成長出奈米晶矽薄膜，接著再使用射頻磁控式電漿鍍膜法成長二氧化鈦薄膜，最後再用蒸著法鍍上一層鋁作為電極，如此完成整個元件的製作。
本文採用場發射掃描式電子顯微鏡(FESEM)、原子力顯微鏡(AFM)、拉曼光譜儀(Raman Spectroscopy)、歐傑電子光譜儀(AUGER)、光致螢光光譜儀(PL)、Spectra Pro500等儀器來分析各層薄膜結構及光電特性，並利用HP4145量測各層不同薄厚對電流增益、Jsc、Voc、Fill Factor、efficiency等重要參數的影響。
實驗結果發現，加入二氧化鈦的確可使電流增益從原先的3.5變成130，如再加入四層(最佳)奈米矽產生的texture接面，則可使電流增益再提升至780，如此證實了TiO2和奈米矽的作用。利用此新結構成長出的太陽電池的初步特性為Voc=260mV、Isc=2.2mA、FF=69.5%、η=4.22%。

In the traditional solar cell with PIN structures, P layer has poor short wavelength response. Besides, there are lots recombinations of electron hole pair generated at p/i interface, thus reduces the conversion efficiency. Furthermore, complicated processes are needed to prepare the PIN structures, thus raises cost. Therefore, in this thesis, we developed a new structure of TiO2/nc-Si/α-Si/ITO/glass for large area and low cost solar cell applications. TiO2 extends the solar absorption spectrum to UV range, and reduces the recombination probability of electron hole pair for its large energy gap (Eg>3.0eV). The nc-Si has nano size grain at surface, which induces a surface texture at both TiO2/nc-Si and TiO2/Al interface; consequently, scattering of injection photon happens at these textured interfaces to enhance the photon absorption in the active layer.
Firstly, use PECVD to deposit the α-Si films on ITO glass substrate and then the nc-Si films under the same temperature by layer-by-layer (LBL) method. Next, use a radio-frequency sputtering system to deposit TiO2 films, and followed by the evaporation of Al electrode. We investigated physical and photoelectric characteristics of the films by FESEM, AFM, Raman Spectroscopy, Auger, PL, Spectra Pro500, and employed HP4145 for current gain, Jsc, Voc, Fill Factor and efficiency.
Experiment results evidence the device with TiO2 raises the phto/dark current ratio from 3.5 to 130. Moreover, the added nc-Si enhances the current ratio from 130 to 780. The initial performances of the new structure solar cell are conversion efficiency =4.22%, Isc= 2.2mA, Voc= 260mV, and FF =69.5%

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