GaAs 표면위에 자기조립 단분자막의 형성, 특성분석 및 패터닝

Abstract

The GaAs is the most widely used semiconductor. The GaAs are promising candidates for a wide variety of applications such as LED, electronic materials, and optical windows. The formation of alkanethiol (H-(CH2)n-SH, n=8, 12, 18) and Octadecylphosphonic acid (CH3-(CH2)17-H2PO3) self-assembled monolayers on n-type GaAs(001) has been systematically studied by contact angle (CA), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and thermal desorption spectroscopy (TDS). We checked the formation of alkanethiols SAMs depending on alkyl chain length, solution concentration and temperature, and immersion time. The CA study revealed that alkanethiols can form SAMs in ammonium hydroxide (NH4OH) and degassed ethanol solvent. We found that high-quality SAMs can be formed by increasing solution concentration at room temperature. And we checked the formation of ODPA SAMs depending on solution type, solution concentration and immersion time. In addition, we observed strong XPS peak in the S 2p region at 162 eV, which implies the formation of chemisorbed ODT SAMs on GaAs, and in the P 2p region at 133.5 eV, which implies the formation of chemisorbed ODPA SAMs on GaAs. Desorption peaks of CH3(CH2)17S+ from ODT SAMs on Au(111) and GaAs surfaces were observed at 170 and 240 °C, respectively, which mean that ODT SAMs on GaAs were much more stable than those on Au(111). And we studied the patterned ODT and ODPA SAMs for using PDMS. Because of the process of combining the surface and the head group, the patterned surface morphology is different. Through the patterned surface, we studied the multilayered film from the layer-by-layer (LBL) deposition. LBL deposition are promising candidates for a variety of applications such as electronic and optical devices, and biochemical sensors. Multilayer composed of poly(ethyleneimine) (PEI) [Poly(allylaminehydrochloride) (PAH)/ poly(sodium 4-styrenesulfonate) (PSS)]3 were grown by spin method. After checked surface morphology to AFM, layer were deposed Ag nanoparticles. Between the Ag nanopaticle and PEI, there are a correlation of pH. We checked various pH range of Ag NPs and PEI, we made the best condition of multilayer of Ag NPs.