製作奈米金顆粒與觀察自我組裝之行為

Abstract

本實驗利用惰性氣體蒸鍍法(inert-gas evaporation)製作奈米金顆粒，藉由控制不同之惰性氣體壓力大小、樣品載台成長溫度，以及蒸鍍速率等，來觀察不同的環境參數對於奈米金顆粒成長之影響。製成之後的樣品再利用原子力顯微鏡(AFM)去觀察粒子成長高度如何隨著環境因素而變化。經由上述多組不同環境參數的變化，研究奈米金顆粒如何成長，推測成長機制以及其成長模型後，與實驗結果對照，並加以討論。 實驗中，推測成長的機制大約分成兩種，第一階段為奈米金顆粒於蒸鍍源上方，由於受到惰性氣體冷卻而開始成長。第二階段成長則是奈米金顆粒蒸鍍於樣品載台後持續成長。藉由精準地控制環境因素來抑制兩種階段的成長，製作出最小之奈米金顆粒，並參考以往之文獻做比較。此外將會對於奈米金顆粒之成長粒徑，做對數機率常態分布函數(Log-Normal Distribution Function)分析，討論粒徑於機率分布之影響。

We present the technique for the production of Au nanoparticles by inert-gas evaporation from a resistive filament. We then discuss the size of Au nanoparticles as a function of evaporation rate, inert-gas pressure, and the temperature of substrate and observe the growth of the Au nanoparticles on substrate. The topography of Au nanoparticles was inspected by using atomic force microscope (AFM) with either contact or tapping modes and analyzed with the software, NIP. It is imperative to be able to produce Au particles of controlled size accurately. We conjecture that there are two possible mechanisms for the growth process. First, the particles coalesce in a region above the metal surface by collisions with gas atoms. Second, the particles formed on substrate will coalesce after the first growth process. Applying the growth model we would like to fabricate the minimum Au nanoparticles by controlling the various parameters exactly. By comparing size distributions for particles produced by inert-gas evaporation, we then show the log-normal distribution function for the Au nanoparticles and discuss it.