- 學位論文
氧化鋅為主的p-n奈米接面特性之研究
Properties of Zinc Oxide-based p-n Junction Nanostructures
摘要
本實驗旨在探討以氧化鋅奈米結構為基礎，完成同質與異質p-n接面結構的開發以及分析，研究中共分為兩部分。 第一部分以水熱法成長p-n 氧化鋅同質奈米結構。我們利用Sb離子做摻雜元素，以水熱法做p型氧化鋅的摻雜，並利用XPS量測、PL光譜分析及電性量測確認Sb離子是否成功摻雜於氧化鋅奈米柱中。並將p型氧化鋅奈米柱成長於n型氧化鋅奈米柱上，得到一p-n接面結構，從電性量測結果證實此為p-n整流的特性，實驗中未能發現電致發光的現象，所以進行第二部分實驗。 第二部分將均勻粒徑的氧化鋅奈米顆粒塗佈於p型氮化鎵薄膜基板上，形成p-n 氮化鎵薄膜-氧化鋅奈米異質結構。在不同厚度氧化鋅奈米顆粒薄膜之穿透光譜量測可知薄膜在可見光範圍有接近100 %的穿透率，可視為透明薄膜。另外，氧化鋅奈米顆粒薄膜表面具有起伏在LED元件應用中可增加出光率。而p-n 氮化鎵薄膜-氧化鋅奈米異質結構的EL光譜分析，在電流值為2 mA時可偵測到發光訊號，當電流值越大，其發光強度越強。此研究中我們以透明的氧化鋅奈米顆粒薄膜和p型氮化鎵薄膜結合成p-n異質結構並完成LED的開發，而透明且表面粗糙的氧化鋅奈米顆粒薄膜將能有效的提升LED的發光效率。
並列摘要
The present study was designed to demonstrate the p-n homo- and hetero- junctions using ZnO-based nanostructures, the study are divided into two parts, the growth of p-n ZnO homojunctions and the fabrications of p-n GaN film-ZnO nanoparticle heterojunctions. In first part, we used hydrothermal method to grow well-aligned p-n ZnO nanorod arrays. Sb was used as dopants for p-ZnO nanorod growth, the systematic study of doping concentrations were also implemented. The high quality and well-aligned p-n ZnO nanorod arrays can be obtained by using tow-step growth, we grew n-ZnO nanorods on SiO2/Si substrate, then p-ZnO nanorods were grown on the n-ZnO nanorods. Due to the epitaxial growth, p-n ZnO nanorod arrays are well-aligned. X-ray photoelectron spectroscopy confirmed the existence of Sb in p-ZnO. The results showed that the lengths of p-ZnO nanorods are influenced by the concentrations of doping solution. The p-n ZnO nanorod arrays exhibit the rectifier behavior from I-V measurements. In second part, ZnO nanoparticles (NPs) with the average diameter of 5 nm were synthesized using the hydrothermal method, the ZnO NPs were then coated onto p-GaN films to form p-n heterojunction. AFM images showed the rough surface of ZnO NP film, which can be used as antireflection layer for the LEDs. Moreover, the transmittance of ZnO NP films is more than 90%, thus, the ZnO NP film can be regarded as the transparent layer. The p-n GaN film-ZnO NP film heterojunction showed the remarkable emission at 434 nm when applied current exceeds 2 mA.