臺灣博碩士論文加值系統

光反應聚合物具有光學非線性效應(例如:二倍頻、三倍頻光的產生)，目前像含偶氮-苯分子(azo-benzene molecules)之類的材料已經廣泛地研究應用在積體光學元件(integrated optics)、波導元件(waveguide component)和記錄元件(memory devices)上。主要由於其具有光同份異構化和分子偶極矩的特性，因此有必要對其做微米、奈米尺度下分子偶極矩的特性研究，甚至進而在奈米尺度下操控其分子偶極矩方向。
由於傳統上都是以光學量測的方式來對此類材料做研究，而在空間解析上受限於光學的繞射極限，所以我們引進了掃描探針的技術於本實驗中，主要以能在大氣環境操作下掃描探針顯微鏡(SPM)來對光反應聚合物 Dispersive Red 1-Poly(methylmethacrykate) (DR1-PMMA) 分子做研究。在實驗起初我們先驗證掃描探針顯微鏡是個觀察DR1-PMMA分子偶極矩排列情況的好工具，而後利用SPM的導電探針來做局部分子偶極矩的方向控制，並觀察其基本物理特性。
我們發現有效的方式為光助探針極化(Photo-assisted poling by probe)，結合此種方式，能成它a能做500~750 nm大小的局部極化。我們結合倒立式顯微鏡，來做激發光源大小的控制，成它a製造間距5µm左右的一維和二維極化點陣列，期野憎荅鄏A往更高的密度邁進，或是做極化的圖形結構。
另外我們發現在光助探針極化的機制下 DR1-PMMA分子的極化行為成一雙指數函數，我們推論在這的兩個反應時間項t1、t2 ；t1為較快的trans ® cis 反應時間項與Laser強度的倒數成正比，t2為較慢的分子方向分布反應時間，正比於分子轉動率的倒數，在相同的Laser強度下其分子轉動率正比於極化電壓。極化點在雷射的輻射下其衰減速度成一單指數的關係，其時間常數在3μw的輻射下約3分鐘、自然衰減的時間常數約數百分鐘。
並且我們先將trans狀態的分子，先以雷射激發到cis的狀態在研究其cis狀態的生存時間，其時間常數約53秒鐘。我們也知道cis的數量與雷射強度成正比關係。

In the past, the photoreactive polymer was studied by the all-optical experiment system. However, there are some shortcomings in the all-optical experiment system. For example, the space resolution limits by optical diffraction limit and the destruction of direction of molecular during the all-optical analysis. So we propose a novel approach based on the scanning probe microscopy (SPM). Local poling was made by the probe of AFM beyond diffraction limit, then measured directly by the electric force microscopy which can avoid the optical destruction. The polymer film (DR1-PMMA) was spin-coated on the ITO glass. The local poling of polymer was made by the probe of Atomic force microscopy which is coating a Ti-Pt film and giving a poling bias with the photo-assisted poling (PAP). The polarization was detected by the electric force microscopy (EFM).
The laser beam is focused at the AFM tip with an inverted optical microscopy. We successed to made the poling dots of one or two dimensions which the period is 5μm and the diameter of the dot is between 500nm to 1μm. The behavior of PAP was expressed by a biexponential function with two response time t1 and t2; t1 is the respond time of trans to cis, which is proportion to the inversion of laser power and t2 is the respond time of orientational distribution of molecular, which is proportion to the inversion of effectively mobility. We also know that the cis life-time is about 53 seconds and the decay time of the poling dot with a 3μw irradiation is 8 min. The population of saturation of cis state is proportion to the laser power.

摘要
第一章 序論
背景簡介
A :基本特性 ------------------------------------------- 2
B :DR1分子的極化
一.分子的極化來源--------------------------------- 4
二.電場極化--------------------------------------- 5
三.光助極化--------------------------------------- 6
C :相關應用與研究動機--------------------------------- 7
第二章 電荷力顯微鏡(EFM)原理
A. 原子力顯微鏡原理----------------------------------- 10
B. 靜電力顯微鏡原理 ---------------------------------- 12
C. AFM導電探針引致極化與量測
a.探針電場分布 --------------------------------- 15
b.AFM的極化與量測的應用------------------------- 16
第三章 實驗架設,結果與分析討論
第一節 樣品製備---------------------------------------- 18
第二節 巨觀電場極化後EFM量測-------------------------- 19
第三節 電荷轉移---------------------------------------- 20
第四節 極化
1. AFM探針光助極化 --------------------------------- 22
2. 物理特性研究
a : 光助極化機制 --------------------------------- 26
b : 光對極化破壞影響------------------------------ 30
c : cis state 的生存時間量測與數目對雷射強度的關係-31
第四章 結論--------------------------------------------------------3

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