探討氧化鋅薄膜的光學、電性與奈米機械特性

The optical, electrical, and nanomechanical properties of ZnO thin films

林承佳(Chen-Jia Lin)

指導教授 ： 劉文仁

共同指導教授 ： 陳元宗(Yuan-Tsung Chen)

義守大學/理工學院/材料科學與工程學系/碩士(2016年)

摘要

本實驗，氧化鋅 (ZnO) 薄膜以射頻磁控濺鍍系統 (Radio frequency magnetic sputtering, RF) 在常溫 (Room Temperature, RT) 下製備。藉由改變不同的氧化鋅薄膜厚度，利用X光繞射儀 (X-ray diffraction) 、超微型光譜儀 (Spactra Smart) 和四點探針 (Four-point Probe) 來研究氧化鋅薄膜的特性。結果得到，在2θ約為34°角時皆有纖鋅礦 (Wurtzite) 結構(002)方向的繞射峰。當氧化鋅薄膜隨著厚度增加，晶粒尺寸而增大。由超微型光譜儀得到薄膜的穿透率在厚度500 Å時最高，約為85%，而其最小反射率約為15%。這表示氧化鋅的薄膜厚度與結晶程度在光學上有很重要的影響性。另外，測量電阻率 (ρ) 後得到，電阻率隨著氧化鋅薄膜厚度增加而減少，是由於晶界與薄膜表面的電子散射所影響，所以較薄的膜有著較好的電阻率。在晶粒尺寸與奈米壓痕得到，硬度的下降與楊氏模數可以合理的解釋與晶粒的增大有相關性，且和Hall-Petch理論與晶粒細化機制的關係一致。整合光學、電學與奈米機械性的結果，厚度為500 Å時的氧化鋅薄膜是適合於光電中的應用。

關鍵字

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並列摘要

In this experiment, ZnO thin films were sputtered on a glass substrate by a radio frequency (RF) magnetron sputtering system at room temperature (RT). The thicknesses (tf) of the ZnO thin film were from 500 Å to 1000 Å. X-ray diffraction (XRD), ultra miniature spectrometer (Spactra Smart) and four-point probe measurements were used to investigate the characteristics of ZnO thin film with various thicknesses. The results exhibited that ZnO has a wurtzite structure with a (002) texture diffraction peak in the 2θ at 34° range. As the ZnO thin film thickness increases, the grain size becomes larger. A ZnO thin film thickness of 500 Å had a transmittance maximum of about 85% and a reflectance minimum of about 15%. That means that thickness and crystallinity of ZnO play an important role in the optical results. Additionally, the four-point probe measuring resistivity (ρ) found that the ρ is reduced as the ZnO thickness increases because grain boundaries and the surface of thin films scatter the electrons, so thinner films have a greater resistance. Between grain size and the nanoindentation results, the decline in the hardness and Young’s modulus can be reasonably concluded to be associated with an enlarged grain size, consistent with the “Hall-Petch” effect and the grain refinement mechanism. Based on the optical, electrical, and nanomechanical results, a thickness of 500 Å of ZnO is suitable for photoelectrical application.

並列關鍵字

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參考文獻

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