GaN/InGaN雙異質結構光伏電池之特性研究及理論光伏特性之計算已在本論文中進行分析比較。自理論模擬結果可得知具備較高銦含量之於 GaN/InGaN雙異質結構光伏電池其轉換效率亦隨之增加。而於實際製備之 GaN/InGaN雙異質結構光伏電池上其銦含量分別為 10%、 12%及 14%之相對應轉換效率則分別為 0.51%、 0.53%及 0.32%。於銦含量 10%時其呈現最高之開路電壓 2.07 V及填充因子 80.67%，而開路電壓及填充因子隨之銦含量之增加而逐漸降低。理論模擬與實驗量測之差異主要來自於 InGaN磊晶層及 GaN/InGaN異面品質隨銦含量增加而呈現劣化所致。
於 1及 120太陽之照光環境下作比較，實際製備而得之 InGaN光伏電池其光伏特性，包含開路電壓、短路電流及填充因子等，其因聚光條件下而獲得之改善程度相較模擬結果來的幅度更加顯著。此結果可暫時歸因於於較高的光致載子注入下其伴隨而來之能陷填充效應所致，其會相對應造成串聯電阻之降低及並聯電阻之提昇。 GaN/InGaN光伏電池之理論計算及實際製備而得之轉換效率改善程度於 1及 120太陽之照光環境下分別為 4.6%及 70.8%，此兩者之差異趨勢呈現一致性之結果。
最後，本研究中亦驗證具備反向粗化表面之 InGaN光伏電池其轉換效率之改善結果。其短路電流密度及轉換效率分別為 0.63 mA/cm2及 1.01%，相較傳統 InGaN光伏電池其特性提昇幅度可達 68.17%及 73.33%。此特性改善之成因可歸因於電極接點之遮蔽效率之降低及表面入射光之反射降低所帶來之效應。

In this dissertation, GaN/InGaN double-heterostructure photovoltaic (PV) cells have been characterized and the theoretical photovoltaic properties were also calculated used for comparison. From theoretical simulation, higher efficiency can be obtained in GaN/InGaN double-heterostructure photovoltaic cells with higher In composition in i-InGaN intrinsic layer. The corresponding conversion efficiency of fabricated GaN/InGaN photovoltaic cells with In compositions of 10%, 12%, and 14% is 0.51%, 0.53%, and 0.32%, respectively. GaN/InGaN photovoltaic cells with In composition of 10% showed high open-circuit voltage of 2.07 V and fill factor of 80.67% and the decrease of open-circuit voltage and fill factor was observed as In composition increasing from 10% to 14%. The difference of GaN/InGaN photovoltaic properties between theoretical simulation and experimental measurement could be attributed to the inferior quality of InGaN epilayer and GaN/InGaN interface generated as the increase of In composition.
When the characteristics of InGaN photovoltaic cells were compared between illumination conditions of one sun and 120 suns, the photovoltaic properties – open-circuit voltage (VOC), short-circuit current (ISC), and filling factor (FF) – measured in fabricated GaN/InGaN photovoltaic cells improved more than those calculated from the simulation. This result could be tentatively attributed to the trap-filling effect under a high injection density of photo-generated carriers, which would relatively reduce the series resistance and increase the shunt resistance. The improvements in the conversion efficiencies of the GaN/InGaN photovoltaic cells between illumination conditions of one sun and 120 suns were 4.6% and 70.8% for simulated and measured conversion efficiencies, respectively. The differences between the simulated results and measurements of actual GaN/InGaN photovoltaic cells are consistent.
Finally, the improvement of conversion efficiency of InGaN photovoltaic cells with inverted textured surface (ITS) was verified in this study. InGaN photovoltaic cells with ITS showed short-circuit current density and conversion efficiency of 0.63 mA/cm2 and 1.01%, which are 68.17% and 73.33% higher than the characteristics of conventional InGaN photovoltaic cells, respectively. The improvement can be attributed to the reduction of both the shading effect of the electrode contact pad and surface reflection of the incident irradiation.

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