這次的研究主要希望應用氮化鎵(GaN)半導體將之光催化分解水產氫，內容包括元件的磊晶結構、光電化學分析、材料特性和半導體黃光製程等相關結合應用於實驗上，目的提升元件抗腐蝕性或者增加產氫效率。
GaN材料也有用於太陽能電池上，同時一般GaN材料的能隙達到3.4eV，而電解水只需要1.23eV，GaN材料吸收太陽能光譜的比例大約只有5%，若太少將導致光電流不佳，因此我們希望利用黃光製程，在同一片基板上並聯一個太陽能電池，來增加光電化學產氫效率，最終目的是不接而外的金屬線，在不加偏壓的0V下，使GaN產氫效率提升。
GaN具有良好的抗腐蝕能力，但在進行產氫時GaN還是會不斷的被消耗，所以希望利用二氧化鈦光觸媒材料幫助吸收長波段光譜之外，有文獻指出觸媒共催化電解水產氫可有效減少對電極的腐蝕，並增加表面粗糙度來減少光的反射，雖效率不如預期增加，但仍有成功減少腐蝕的狀況。
最後我們嘗試眾多結構，使用n-InGaN且預計透過在底部增加super lattice的結構，除了增加長波長吸收效率之外，也可提升上半部GaN的晶體品質。此外我們還希望利用AlGaN晶格不匹配，來探討由於磊晶層晶格不匹配的關係產生的壓電場，來幫助載子的分離。

In this research, we mainly discuss applying Ⅲ-Nitride semiconductor of photoelectrochemical splitting water on the working electrode, including the properties of materials, epitaxy structure, lithography and combining the application in photoelectrochemical analysis, the semiconductor manufacturing as well. For this purpose, we hope to improve device stability also the efficiency of hydrogen and oxygen from splitting water with light illuminating.

Photoelectrochemical reaction (PEC) only needed 1.23eV to generate hydrogen but Gallium Nitride (GaN) is a large band gap semiconductor. Therefore, we use lithography, such as combining a solar cell to improve photocurrent and we accomplish the zero-bias photoelectrolysis of water under visible illumination without assisted bias.

GaN has good corrosion resistance in acid-based solution but PEC reaction still consume n-GaN. Thus we coat TiO2 on n-GaN to enhance the absorption of the solar spectrum. Nevertheless, it didn’t achieve our expectation to increase efficiency. Still it decreased the corrosion of n-GaN.

Finally we tried many structures. We grew AlGaN or InGaN and super lattice layer on GaN-base materials to improve the electron-hole pair separation on the working electrode due to built-in polarization fields by the lattice mismatch and extend the absorption spectrum to visible light. Then we discussed the results which reached our expectation.

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