Preparation of in situ Patterned ZnO Thin Films by Microcontact Printing

In situ patterned zinc oxide thin films were prepared by precipitation of Zn(NO$_3$)$_2$ aqueous solution containing urea and by microcontact printing using Self-Assembled Monolayers(SAMs) on A1/SiO$_2$/Si substrates. The visible precipitation of Zn(OH)$_2$ that was formed in the Zn(NO$_3$)$_2$ aqueous solution containing urea was enhanced with an increase of the reaction temperature and the amount of urea. As the reaction time of Zn(NO$_3$)$_2$ with urea was prolonged, the thickness and grain size of Zn(OH)$_2$ thin layers were increased, respectively. The optimum precipitation condition was at 80$\^{C}$ for 1 h for the solution with the ratio of Zn(NO$_3$)$_2$ to urea of 1 : 8. Homogeneous ZnO thin films were fabricated by the heat treatment of 600$\^{C}$ for 1 h of Zn(OH)$_2$ precipitation on Al/SiO$_2$/Si substrate. This was available to the in-situ patterned ZnO thin films with uniform grain size. Hydrophobic SAM, Octadecylphosphonic Acid(OPA) and hydrophilic SAM, 2-Carboxyethylphosphonic Acid(CPA) were applied on the Al/SiO$_2$/Si substrate by microcontact printing method. In situ patterned ZnO thin film was successfully prepared by the heat treatment of Zn(OH)$_2$ precipitated on the surface of hydrophilic SAM, CPA.

Microcontact Printing을 이용한 미세패턴 ZnO 박막 제조

Zn(NO$_3$)$_2$ 수용액과 urea[CO(NH$_2$)$_2$]를 이용한 침전법과 Self-Assembled Monolayers(SAMs)를 이용한 microcontact printing 방법으로 미세 패턴화된 ZnO 박막을 Al/si0$_2$/si 기판 위에 제조하였다. Zn(NO$_3$)$_2$와 urea를 혼합하여 제조한 Zn(OH)$_2$ 박막은 침전온도와 urea 량이 증가할수록 Zn(OH)$_2$의 침전량이 증가하였고 Zn(NO$_3$)$_2$와 urea의 반응 시간이 증가함에 따라, Zn(OH)$_2$ 박막의 두께와 입자 크기가 증가하였다. Zn(NO$_3$)$_2$와 urea의 혼합비를 1 : 8, 용액의 침전 온도를 오일 bath내에서 8$0^{\circ}C$, 반응시간을 1시간으로 하여 Al/SiO$_2$/Si 기판 위에 침전된 Zn(OH)$_2$ 박막을 $600^{\circ}C$에서 1시간 동안 열처리하여, 미세 패턴을 형성하기 위한 균질한 크기의 ZnO 박막을 제조할 수 있었다. Microcontact printing방법으로 소수성과 친수성 SAMs인 Octadecylphosphonic Acid(OPA)와 2-Carboxyethylphosphonic Acid(CPA)를 각각 Al/SiO$_2$/Si 기판 위에 선택적으로 흡착한 후에 친수성 SAM인 CPA위에 Zn(OH)$_2$를 침전시켜 미세 패턴화된 ZnO 박막을 제조할 수 있었다