近年來隨著替代能源的迫切需求與太空工業的蓬勃發展，太陽光電的前景備受注目，銅銦鎵硒(CIGS)薄膜太陽能電池具有輕薄、可商業化製程和高效率等優勢，因此本研究從CIGS太陽能電池之背接觸介面切入，成功以電漿輔助硒化製備出具有c軸水平於表面之優選晶向的WSe2中間層，藉著WSe2這種二維材料所具備的膜層內高導電度的特性改善背接觸介面的載子傳輸行為，此外WSe2亦擁有較高導帶的能帶結構，促使流向背電極端的電子被反彈以減少載子複合。另一方面，這種特殊的優選晶向在材料微結構上扮演重要腳色，促使鎵原子嵌入WSe2中間層之間，並引起WSe2電子結構改變，從而優化背接觸介面能帶結構與調控吸收層鎵梯度，綜合以上效應可以將Jsc提升至38 mA/cm2，效率上也從12.5%增進到14.3%。

Recently, with the increasing demands of green energy and space industry, solar energy attracted much attention. Copper indium gallium selenide (CIGS) thin film solar cells have the advantages, such as commercial process, lower material usage and higher conversion efficiency with tunable band structure. Thus, in the prospective of back contact in CIGS solar cells, we successfully prepared WSe2 interfacial layer with specific orientation of c-axis parallel to the surface through plasma-enhanced selenization process. WSe2, a kind of two dimensional materials, has better conductivity in in-plane direction. We expected the special characteristic may improve the carrier transportation at back contact. In addition, with higher conduction band minimum in band structure of WSe2, the electrons flowed toward back contact may be blocked, so recombination rate will be reduced. On the other hands, the special preferred orientation play a important role on tuning the gallium gradient in absorber layer. Combining above effect, Jsc value is significantly improved to 38 mA/cm2, and the efficiency is increased from 12.5% to 14.3%.

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