氮化鎵是製作發光二極體最主要的材料之一，而氮化鎵的直接能隙(3.4eV)與氮化銦直接能隙(0.7eV)所混合的三元化合物氮化銦鎵(InGaN)可做為發光二極體以及太陽能電池元件。
由於p型氮化鎵之功函數(7.5eV)大於常使用的金屬(6eV)，使得在電極接面處產生了蕭基接觸現象，進而影響了元件的特性。本論文為了改善p型電極的接觸特性，我們製作了傳輸線實驗，並分別量測在不同退火氣體包括氮氣(N2)、氧氣(O2)、潔淨乾燥空氣(Clean Dry Air, CDA)時的I-V特性曲線。我們從CDA這一組實驗數據中得到最低的特徵接觸電阻，且其I-V曲線最接近歐姆特性，而採用此參數的發光二極體會比以氮氣為退火氣體的有顯著較低的啟動電壓。
在製作過程中，我們發現製作p型電極微影製程時，負光阻會因高台邊緣的高低落差過大，造成旋轉塗佈不均勻，使得將光阻移除並帶走光阻上的金屬(lift-off) 的製程出現瑕疵而造成漏電流現象，為了改善漏電流現象，我們調整了製程參數，使得負光阻可以有效的反轉成所要的圖型，去除了漏電流現象，使得太陽能電池元件可得到2V高開路電壓。

GaN is one of the major materials for fabricating light-emitting diodes (LED). The ternary compound semiconductor InxGa1−xN having a direct band gap from about 0.7eV to 3.4 eV is applicable in the fields of light-emitting diodes and solar cells.
Because p-GaN has a larger work function(7.5 eV) than metals (under 6eV), p-GaN metal contact often behaves like Schottky contact that deteriorates the performance of the devices.
In order to solve this problem, this study is aiming at fabricating ohmic p-type contacts. Based on the principle of transmission line model, experiments under different annealing gases including N2, O2 and Clean Dry Air (CDA) were performed. I-V curves and specific contact resistances were measured and compared.
We obtained the lowest specific contact resistance while using CDA annealing gas, and its IV characteristic is the most near ohmic. As a result, the turn-on voltage of our LED has been significantly reduced. Moreover, in the photolithography process, we observed nonuniform negative photoresist spreading due to large mesa height. That caused incomplete photoresist reversal and lift-off leading to short circuit between p and n electrodes. We adjusted parameters of the photolithography process and eliminated leakage current. As a result, the open-circuit voltage of our solar cell has been increased to 2V.

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