以電漿輔助化學氣相沉積法開發雙接面矽薄膜太陽能電池

Abstract

在本研究中，主要目標為開發雙接面矽薄膜太陽能電池，因此從兩個方向進 行研究，一個為非晶矽薄膜堆疊太陽能電池，一個為微晶矽薄膜開發再延伸到非 晶矽及微晶矽堆疊薄膜太陽能電池。本研究是利用射頻電漿輔助化學氣相沉積系 統來沉積非晶矽和微晶矽薄膜。 在非晶矽薄膜堆疊太陽能電池的研究中，藉由調變上層太陽能電池的吸收層 厚度來達到電流匹配，此外也加入能帶漸變的應用來改善短路電流。在穿隧複合 接面上，藉由調變非晶矽n-type 層的厚度來減少此層所造成的光線吸收，另外 加入微晶矽n-type 層來改善原本由非晶矽n-type 層和 p-type 層所造成的反 向二極體。 在微晶矽薄膜開發方面，藉由調變總流率、電漿功率和氫氣稀釋比例來探討 微晶矽薄膜的材料特性。微晶矽薄膜是在高壓力以及高電漿功率中成膜。在X 射線散射儀的量測和光感應中都顯示良好的材料特性在較低的電漿功率和非晶 矽轉換成微晶矽的過渡區。

In this study, the major objective is to develop silicon based tandem solar cell. There are two directions to achieve this objective: development of a-Si:H / a-Si:H tandem solar cell and deposition and characteristic of the intrinsic μc-Si:H thin film to fabricate a-Si:H / μc-Si:H tandem solar cell. Both a-Si:H and μc-Si:H were deposited by plasma-enhanced chemical vapor deposition (PECVD) system at 27.12 MHz In the part of a-Si:H / a-Si:H tandem solar cell, we varied the thickness of top cell to achieve current matching. Beside, the band-gap profiling is used in buffer grading to improve short-circuit current density (Jsc). μc-Si:H n-layer is applied in tunneling recombination junction (TRJ), it shows no reverse electric field against the built-in voltage of top and bottom cell compared with the TRJ with μc-Si:H n-layer. In the part of intrinsic μc-Si:H thin film deposition, The effect of total flow rate, power and hydrogen dilution ratio on intrinsic μc-Si:H thin film characteristic has been studied. The μc-Si:H thin films were deposited under high pressure and high power condition. The transition region from a-Si:H to μc-Si:H shows a good material characteristic both in X-ray diffraction spectroscopy (XRD) and photosensitivity.