玻璃深蝕刻技術開發應用於複合量子點合成之微反應晶片製作
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2006
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本研究主要製作一應用於合成複合量子點之全玻璃微反應晶片。並將微流體系統之微流道、微混合器、白金加熱器及溫度感測器整合在此單晶片上。在玻璃微流道的製作方面，以較厚的光阻及鉻/金薄膜作為蝕刻保護層，可有效減少針孔現象的產生；並將蝕刻金膜之王水，換成不會破壞光阻之碘化鉀溶液，可使微流道邊緣之缺陷部份獲得改善。另外，在退火溫度對玻璃側向蝕刻(lateral underetching)的實驗中，證實了當退火溫度到達600 ℃時，可有效抑制Pyrex 7740嚴重的側蝕現象，經氫氟酸(HF)溶液蝕刻10分鐘後，其流道斷面寬度從498 m縮減至278 m，側蝕比(lateral underetching ratio)可從5降低至0.96。而Corning 1737與Soda-lime雖然不須經過退火處理過程，即可獲得較小之側蝕比，但是Soda-lime之表面粗糙度較差，因此本實驗選擇Corning 1737作為微反應晶片之基材。
在複合量子點的製備上，微流體系統擁有良好的質傳及熱傳效果，可以精確的控制反應溫度、反應時間及溶質濃度，因此可有效提升量子點的品質及改善奈米粒徑分佈不佳的問題。除此之外，對於反應溫度控制在200 ℃至280 ℃ 的硒化鎘(CdSe)，其吸收波峰從450 nm移至550 nm，能隙大小從2.58 eV降低至2.3 eV，並推估其粒徑大小為2-6 nm。由此可知，當反應溫度升高時，吸收波峰往紅色波長的方向移動，而能階則隨著粒徑的增大而變小。
In this report, we fabricated an all-glass microreactor chip and used it to synthesize compound quantum dots. A microreactor chip integrates micro channels, a micro mixer, a Pt heater, and a temperature sensor on one glass chip. During fabrication of micro channels, a thick photoresist and Cr/Au layer were used as etching masks. Such etching masks could sufficiently reduce pinhole phenomenon. In addition, if we replaced aqua regia with KI solution, it would not damage the photoresist. Therefore, it could improve defects at edge of micro channels. If we considered annealing factor with different glass materials, the experimental results showed that if we annealed Pyrex 7740 to 600 ℃ and etched micro channels by using HF for 10 min, the channel width was found to be reduced from 498 m to 278 m. The lateral underetching ratio decreased from 5 to 0.96. Thus, we could improve the large lateral underetching of glass (Pyrex 7740) by annealing. However, the surface roughness of micro channels was high. On the other hand, it was not necessary for Corning 1737 to be annealed. We could get smaller lateral underetching ratio and better surface roughness of micro channel. As for Soda-lime, it didn’t have any relationship between annealing and lateral underetching ratio, but the surface roughness was high. Consequently, Corning 1737 was suitable material for making microreactor chip. For preparation of compound quantum dots, microfluidic systems have good characteristic on good mass and heat transfer. It can precisely control the reaction temperature, reaction time, and concentration of the solute. Therefore, unlike traditional reaction which is used to produce quantum dots with different sizes, we can use microfluidic systems to synthesize uniform quantum dots. When the reaction temperature was controlled from 200-280 ℃, the absorbance peak was found to increase from 481 nm to 538 nm. its corresponding band gap was discovered to decrease from 2.58 eV to 2.3 eV.
In this report, we fabricated an all-glass microreactor chip and used it to synthesize compound quantum dots. A microreactor chip integrates micro channels, a micro mixer, a Pt heater, and a temperature sensor on one glass chip. During fabrication of micro channels, a thick photoresist and Cr/Au layer were used as etching masks. Such etching masks could sufficiently reduce pinhole phenomenon. In addition, if we replaced aqua regia with KI solution, it would not damage the photoresist. Therefore, it could improve defects at edge of micro channels. If we considered annealing factor with different glass materials, the experimental results showed that if we annealed Pyrex 7740 to 600 ℃ and etched micro channels by using HF for 10 min, the channel width was found to be reduced from 498 m to 278 m. The lateral underetching ratio decreased from 5 to 0.96. Thus, we could improve the large lateral underetching of glass (Pyrex 7740) by annealing. However, the surface roughness of micro channels was high. On the other hand, it was not necessary for Corning 1737 to be annealed. We could get smaller lateral underetching ratio and better surface roughness of micro channel. As for Soda-lime, it didn’t have any relationship between annealing and lateral underetching ratio, but the surface roughness was high. Consequently, Corning 1737 was suitable material for making microreactor chip. For preparation of compound quantum dots, microfluidic systems have good characteristic on good mass and heat transfer. It can precisely control the reaction temperature, reaction time, and concentration of the solute. Therefore, unlike traditional reaction which is used to produce quantum dots with different sizes, we can use microfluidic systems to synthesize uniform quantum dots. When the reaction temperature was controlled from 200-280 ℃, the absorbance peak was found to increase from 481 nm to 538 nm. its corresponding band gap was discovered to decrease from 2.58 eV to 2.3 eV.
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微反應晶片, 側蝕現象, 複合量子點, microreactor, lateral underetching ratio, compound quantum dots