如今產業上的太陽能電池發展多以矽晶圓為主要材料，因為矽晶圓本身材料較貴，且在矽晶圓上產生PN接面 (PN junction) 多是利用離子佈植或雜質擴散的方式，這兩種方式皆是高溫製程，相對的製程成本較高，是以本研究希望以沉積薄膜的方式，在矽晶圓上覆蓋相對摻雜特性的含氫非晶矽薄膜完成異質的PN接面。 因此企圖找出高摻雜濃度 (高導電率) 且低吸收係數的P型含氫非晶矽薄膜，是本研究前半段的目的，因為高導電率、高摻雜的薄膜是較適合應用於製作異質接面太陽能電池。而後半段的目的則是希望對元件做優化的動作，不論是薄膜或基板厚度、半導體─半導體或金屬─半導體接面都是需要被探討並改善的地方，研究中也將針對部分作分析與探討。 實驗中以射頻磁控濺鍍法沉積的P-type a-Si:H薄膜，經過添加硼顆粒於濺鍍源、調變氫氣與氬氣分壓比例和快速熱退火處理後，已具備有高導電率的特性，將其沉積在N-type c-Si基板上，並完成異質接面太陽電池的製作。 研究與分析完本實驗自製的太陽能電池，得到一有1.9%轉換效率的異直接面太陽能電池，其開路電壓VOC約為0.5 V，短路電流密度JSC約為9.6 mA/cm2，填充因子FF約為39.7%。 Silicon wafer is the main material for silicon solar-cell industry. However, to generate a silicon P-N junction solar cell, the material cost and the high-temperature process are expensive. In this study, we aim the deposition of the hydrogenated amorphous silicon (a-Si:H) thin film on the silicon wafer to generate the heterojunction silicon solar cell. The high doping concentration (high conductivity) and the low absorption coefficient are the important parameters for the P-type a-Si:H thin film, because of the higher doping of the a-Si:H thin film can achieve the higher conversion efficiency of the heterojunction solar cell. We also optimized the thicknesses of the a-Si:H thin film and the substrate wafer to improve the conversion efficiency. Besides, the interfaces of the semiconductor ─ semiconductor and metal ─ semiconductor have been analyzed explored to improve the performance of the solar cells. The a-Si:H heterojunction solar cells have been fabricated using radio-frequency magnetron sputtering to deposit a P-type a-Si: H film on the N-type Si wafer. The sputtering target is a bulk P-type Si with boron grains on it. We modulated the hydrogen and argon partial pressure ratio and the rapid thermal annealing to control the quality of the P-type a-Si:H thin film. The results show the P-type a-Si:H thin film behaved highly conductive. After depositing the P-type a-Si:H thin film on the N-type Si substrate to form the heterojunction solar cell, the conversion efficiency of the solar cell is 1.9%, the open circuit voltage VOC is about 0.5 V, the short-circuit current density JSC is about 9.6 mA/cm2 and fill factor FF is about 39.7% .
