Au oxide layer pattern formation by F2 laser irradiation under ambient conditions

F₂ laser emits high-energy photons of 7.9 eV (157 nm), which is much higher than the bonding energy of molecules (~4 eV). The high energy photons of F₂ laser excite the Schumann-Runge continuum of O₂ molecules and forms electronically excited O atoms having strong oxidative nature. The F₂ laser light are utilized for various photochemical and oxidative surface modification of materials. Au is known as the noblest metal, and the high oxidation resistance is utilized for various applications. We formed Au oxide layer pattern on the Au surface by F₂ laser irradiation under the ambient condition. We estimated the stability of the Au oxide layer under various condition and utilized the Au oxide pattern for protective layer of Au-S bond formation by disulfide on Au substrate surface.