| Summary: | 碩士 === 國立臺灣科技大學 === 工程技術研究所 === 98 === Due to the progress in synthesizing GaN films, GaN/GaInN light-emitting diodes (LEDs) have successfully developed and are the most important optoelctronic component. Therefore, group III nitrides have become important semiconductor materials. Group III nitrides have two kinds of structures, zinc blende and wurtzite, depending upon the process conditions. Zinc blende belongs to an indirect semiconductor and wurtzite with good luminescent properties a direct one.
Our experiments involve the following three approaches.
1. The nickel nitrate solution was spin-coated on silicon substrates. The dried substrates were pyrolyzed at 650oC for 15 minutes followed by the reduction at different temperatures (850 oC, 750 oC, 650 oC) for 30 minutes. Finally, the GaN nanowires were synthesized on those catalyst-covered substrates at different temperatures (900 oC, 800 oC, 750 oC) for 30 minutes.
2. The GaN nanowires were grown at different temperatures (900 oC, 800 oC, 750 oC) for 30 minutes by using the gold, nickel or nickel-gold catalyzed substrates. These catalysts were deposited by PVD followed by annealing at different temperatures for 30 minutes. Additionally, different substrates such as AAO and self-fabricated porous alumina disks were also used for studing the effect of surface morphology of substrates on the growth of GaN nanowires.
3. GaN nanowires were grown by different Ga precursors, GaCl3 and Ga2Cl4, by using the growth condition obtained from the approaches 1 and 2. The growth behaviors of these two precursors were investigated.
The GaN nanowires with good morphology were synthesized by using the GaCl3 and Ga2Cl4 as precursors via APCVD. Besides, we find the best parameters for the growth of GaN, the relationship between the morphology and distribution of products, and the effects of catalysts on the nanowire growth.
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