(一)氧化鋁鋅透明導電膜
利用射頻濺鍍氧化鋁混合氧化鋅陶瓷靶材，在藍寶石基板上沉積摻雜鋁之氧化鋅透明導電薄膜。經由調變氬氣流量沉積厚度為0.6μm之薄膜，再以700°C到1000°C真空環境下退火一分鐘。並做電特性光特性以及X-ray繞射分析。氧化鋁鋅薄膜可獲得電阻率7×10-4到9×10-4 ohm．cm，載子濃度為3.37x1020 cm-3，移動率為25.8 cm2 /Vs，並且在可見光範圍有良好的穿透特性。利用Ti(20nm)/Al(300nm)金屬層作為氧化鋁鋅薄膜之歐姆接觸電極，並經由TLM量測獲得低的比接觸電阻值為6.89x10-6 ohm-cm2。

(二)低電阻之Ag/AZO雙層透明電極
Ag/AZO雙層組合之導電薄膜在可見光範圍具有光穿透特性並且擁有低的片電阻值約2 ohm/sq，這比起一般廣泛被使用的透明導電電極還要擁有更低的電阻率。在這部分研究當中，先在玻璃基板上利用熱蒸著鍍上一層很薄的銀金屬，再利用磁控濺鍍沉積摻雜鋁之氧化鋅薄膜。當銀的厚度接近14nm以及氧化鋅鋁薄膜在200nm厚度時，可見光範圍的穿透率約在50-60%。氧化鋁鋅薄膜的電特性與穿透率主要受致於銀金屬層的影響。Ag/AZO透明導電層可以廣泛的被用來取代傳統的太陽能電池之鋁金屬電極。由於鋁電極會造成光吸收，因此Ag/AZO透明導電層可以改善其元件效率。

(三)P型砷化鎵之i-ZnO/AZO低電阻值與透明毆姆接觸
利用射頻磁控濺鍍系統沉積氧化鋅鋁(AZO)和未摻雜氧化鋅(i-ZnO)/氧化鋅鋁雙層薄膜於P型氮化鎵基板。氧化鋁鋅薄膜厚度在300nm時，400nm到800nm可見光波長範圍之穿透率達80%–92%。沉積歐姆接觸電極後再接著熱退火處理。p-GaN/AZO接觸呈現非線性的電特性。無論如何，在AZO薄膜與p-GaN之間插入i-ZnO層可有效改善電特性。另外，在氮氣環境下退火550°C兩分鐘時，在p-GaN上的i-ZnO/AZO接觸薄膜可以得到1.644×10-5 ohm-cm2低的比接觸電阻值。由歐傑電子光譜分析i-ZnO/AZO與p-GaN接面處，得知鎵原子在熱退火後接面處外擴散因而降低比電阻值。

(I) Transparent conductive oxides of Al-doped ZnO
Transparent conductive Al-doped ZnO thin films were prepared on sapphire substrate by radio frequency (RF) diode sputtering with Ar gas and an Al2O3-mixed ZnO ceramic target. The samples, with constant thickness of 0.6μm, were prepared under various Ar partial pressure ratios in the range of 5sccm to 14sccm, then annealed at temperatures ranging from 700°C to 1000°C for 1min in a vacuum furnace. The electrical, optical and X-ray diffraction properties were evaluated. The produced AZO films showed resistivity in the range of 7×10-4 to 9×10-4 ohm．cm, carrier concentration of 3.37x1020 cm-3, Hall mobility of 25.8 cm2 /Vs, and the property of transmittance in the infrared wavelength. The ohmic characteristics were derived using metallic layers of Ti(20nm)/Al(300nm) as electrodes applied to the Al-doped ZnO films. A low specific contact resistance of 6.89x10-6 ohm-cm2 was observed by the transmission line method (TLM).
(II) Low resistivity of Ag/AZO bi-layer transparent electrode
The bi-layer films of Ag/AZO structure having the optical transmittance in the visible range and the low sheet resistance of about 2 ohm/sq than the widely used transparent conducting oxide electrodes. In this study, a siliver layer was evaporated on glass with a very thin thickness and Al-doped ZnO film (AZO) was then deposited on Ag layer by magnetron sputtering. When the thickness of Ag layer is nearly 14nm, accompanied with the AZO layer with the thickness of 200nm, the transmittance of 50-60% at the visible range can be observed. The electrical properties and optical transmittance of AZO film are mainly influenced by the Ag layer. The Ag/AZO transparent conducting layers can be widely used to replace the conventional Al grids electrode on solar cells. Also it can efficiently improve the insufficient light absorption due to the shadow of Al grids uses.

(III) The low resistivity and transparent i-ZnO/AZO ohmic contacts to p-type GaN
Al-doped ZnO (AZO) and un-doped ZnO (i-ZnO)/AZO bilayer films were deposited on p-type GaN by RF magnetron sputtering system. The transmittance of an AZO film with a thickness of 300 nm was 80%–92% for the light in the wavelength range of 400 and 800 nm. The depositions were followed by thermal annealing to form Ohmic contacts. The p-GaN/AZO contacts exhibited a non-Ohmic electrical characteristic. However, electrical characteristic could be greatly improved by insertion of i-ZnO between AZO film and p-GaN layer. In addition, the i-ZnO/AZO contact films yielded a low specific contact resistance of 1.644×10-5 ohm-cm2 on p-GaN when annealed at 550°C for 2 min under a nitrogen ambient. Auger electron spectroscopy analyses of the i-ZnO/AZO and p-GaN interface indicated that Ga atoms had out-diffused at the interface region after the thermal annealing process, resulting in a decrease in contact resistance.

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