本論文的研究目的是藉由含鋁奈米粒子的透明導電薄膜氧化鋅來改善氮化鎵發光二極體的出光效率。成長鋁摻雜氧化鋅薄膜是利用濺鍍機同時濺鍍氧化鋅(99.99%)及鋁(99.99%)靶材，固定濺鍍氧化鋅的射頻功率為100瓦，改變濺鍍鋁的直流功率從0瓦增加到13瓦以得到不同鋁含量的鋁摻雜氧化鋅薄膜。熱處理後的鋁摻雜氧化鋅薄膜之載子濃度一開始會隨著鋁含量增加而增加，但是當鋁含量超過鋁在氧化鋅內的溶解度時，載子濃度會隨著鋁含量增加而降低，而且過量的鋁會形成中性的原子並產生析出。在本研究中，鋁功率為0、4.5、7瓦的氧化鋅薄膜由於載子濃度會隨著鋁含量增加而增加，故無鋁析出，但當鋁功率為10、13瓦時，會析出鋁的奈米粒子。在將測試出的具鋁奈米粒子之鋁摻雜氧化鋅薄膜成長於發光二極體的p型區域之前，會先使用電子槍蒸鍍機成長一層薄的鋁摻雜氧化鋅薄膜(10nm)，再將測試出的不同鋁含量之鋁摻雜氧化鋅薄膜(170nm)成長於發光二極體的p型區域，這是為了避免濺鍍機的電漿會破壞p型金屬薄電極，並比較發光二極體的出光效率。在量測發光二極體的光強度之前會先蝕刻掉p型金屬接墊上及周圍的雙層鋁摻雜之氧化鋅薄膜，如此可避免電流注入氧化鋅薄膜內，並排除不同電阻率的氧化鋅薄膜具有不同程度電流散佈對發光二極體出光效率的影響。成長鋁功率為0、4.5、7瓦的鋁摻雜氧化鋅薄膜於發光二極體上，其出光強度較傳統發光二極體增強約10%，這是因為氧化鋅薄膜藉由厚度的控制扮演著抗反射膜的角色；成長鋁功率為10瓦的鋁摻雜氧化鋅薄膜於發光二極體上，出光強度可增加約20%，此氧化鋅薄膜內具有鋁奈米粒子，使得原本在氧化鋅及空氣界面形成全反射的光能藉由鋁奈米粒子的散射改變光的行進方向，進而可被萃取。然而，當成長鋁功率為13瓦的氧化鋅薄膜，發光二極體的出光強度卻是下降的現象，這是因為此氧化鋅薄膜內含太多且太大的鋁奈米粒子產生嚴重的背向散射所造成。最後再增加氧化鋅薄膜電流散佈的功能以進一步提昇發光二極體出光強度。

The research in this paper was to use transparent and conductive ZnO films with Al nano-particles (Al doped ZnO, AZO) to increase the extraction efficiency of GaN-based LEDs. The AZO films were deposited by sputtering ZnO(99.99%) and Al(99.99%) targets simultaneously. Fixing the ZnO RF power of 100W and changing the Al DC power from 0 to 13W could deposit different Al concentration AZO films. The carrier concentration of AZO films after annealing would increase with increasing Al concentration at first. However, while the amount of Al was more over than the dissolution of Al in ZnO, the carrier concentration would decrease with increasing Al concentration and the excess Al would form neutral atoms and segregate. In this research, the AZO films with Al DC power of 0, 4.5, 7W would not have Al segregation and with Al DC power of 10 and 13W would segregate Al nano-partlcles. Before the different Al concentration AZO films were deposited on p-type area of LEDs, a thin AZO film (10nm) was deposited by e-gun system. This was due to the plasma of sputter would damage the transparent contact of LEDs. Then, different Al concentration AZO films (170nm) were deposited on p-type area of LEDs to compare the light intensity of LEDs. Before measuring the light intensity of LEDs, the bi-layer AZO films on and surround the p-type bonding metal was etched. Thus, the current spreading of AZO films would be removed and the different resistance of different Al concentration AZO films would not affect the light extraction efficiency of LEDs. The light intensity of LEDs deposited with AZO films with Al power of 0, 4.5, 7W increased 10~15% than conventional LEDs. This was due to the AZO films played a role of anti-reflection coating (ARC). The light intensity of LEDs deposited with AZO film with Al power of 10W increase about 30%. The AZO film with Al power of 10W had Al nano-particles. The Al nano-particles could scatter the light to change the direction of the light which formed total reflection at the interface of AZO and air and more light could be extracted. However, when the LEDs deposited with AZO film with Al power of 13W, the light intensity of LED decreased contrarily. This was due to the AZO film with Al power of 13W had too much and too large Al nano-particles to form serious back scattering. Finally, the current spreading function of AZO films was added to improve the light extraction efficiency of GaN-based LEDs further.

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