108年
姓名 丁建芳 Chien-Fang Ding
題目

複合式紫外光雷射直寫退火製程於導電薄膜之研究

Study of Compound Ultraviolet Laser Direct-Write Annealing Process on Conducting Thin Film Fabrication
大綱

摘要

本研究使用紫外雷射直寫退火技術在兩種不同型態的導電薄膜：摻鋁氧化鋅(ZnO:Al, AZO)和石墨烯(Graphene)，並針對材料退火前退火後進行光、電、材料、結構、拉曼光譜等性質去分析薄膜的特性。

在AZO薄膜之雷射退火實驗中，結果顯示調變雷射能量密度和退火速度對於材料之光學與電學特性影響十分顯著。雷射退火處理後，AZO材料之可見光穿透光譜有些許的變化，平均穿透率約為84.7％。另一方面，退火處理後的AZO薄膜，最大電阻率從1.15Ω·cm降至1.17×10-2Ω·cm，比初始值低了近99％。此外，雷射能量密度不僅影響薄膜的結構特性，還能改善了薄膜的結晶程度，而不至於影響到薄膜厚度以及薄膜中元素的成分濃度。而隨著雷射能量密度的增加，薄膜的表面粗糙度也逐漸增加。此外，根據X-射線繞射分析(XRD)，在AZO薄膜材料中，對應於(002)方向的主峰之強度也會隨著雷射能量密度的增加而提升。然而，由於雷射退火製程屬於低溫熱處理，因此，退火處理後的平均估算之晶粒大小(20nm)略小於未退火處理的AZO薄膜(21.7nm)。

在石墨烯材料的雷射退火實驗中，同樣地，雷射能量密度對於石墨烯薄膜的電學性質有很大影響。雷射退火處理後，石墨烯薄膜的片電阻值從262.22Ω/ sq大幅下降至97.27Ω/ sq，比初始值低約62.9％。在拉曼光譜的結果中，ID / IG從0.75降至0.3，顯示出石墨烯結構中的缺陷減少。此外，在雷射的選擇性加工與石墨烯的電熱實驗中，透過調變雷射的能量密度與退火速度，依照使用者的期望，可以得到對應的片電阻值或其他材料特性。

關鍵字：雷射退火、鋁摻雜氧化鋅、石墨烯、選擇性雷射加工、電熱響應

Abstract

  This study investigated the photon thermal treatment by ultraviolet laser direct-write system on two promising conducting films, including ZnO:Al (AZO) and graphene. The films characteristics were systematically analyzed, using a 4-point probe instrument, an ultraviolet-visible-near-infrared (UV-vis-NIR) spectrophotometer, X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), before and after the laser annealing process.

  In the laser annealing process of AZO material, the experimental results indicated that varying the laser fluence and annealing speed affected the optical and electrical properties of the AZO films. After the laser annealing process, there was a slight change in the visible region with approximately 84.7 % of transmittance spectra.The maximum resistivity values of the annealed AZO films decreased from 1.15 Ωcm to 1.17 × 10−2 Ω.cm,approximately 99 % higher than the initial value. In addition, the laser fluence not only influenced the structural properties of the films, but also improved the crystallinity of the films after the laser annealing process, with minimal changes in the thickness of the films and the concentration of the elements in the films. The root mean square surface roughness (Rrms) of the films gradually increased as the laser fluence increased. Moreover, according to the XRD pattern of the films, the intensity of the main peak corresponding to the (002) direction increased as the laser fluence increased. The average grain size (20 nm) of the annealed films, determined using the Scherrer equation, was smaller than that of the as-deposited thin film (21.7 nm) due to the low temperature effect in the laser annealing process.

  In the laser annealing process of graphene material, the laser fluence had a great effect on the electrical properties of the graphene thin films. The sheet resistance of printed graphene thin films decreased from 262.22 Ω/sq to 97.27Ω/sq after laser annealing, approximately 62.9 % lower than the initial value. In addition, based on the results of Raman spectrum, the ID/IG decreased from 0.75 to 0.3, showing that the structural disorder in graphene structural was reduced. Furthermore, the selective laser processing and the electrothermal response test of printed graphene thin film on a glass substrate were conducted to show the potential of multi-zone heater and further applications.

Keyword: Laser annealing, aluminum-doped zinc oxide, graphene, selective laser processing, electrothermal response.