The structure of the self-assembled monolayers of decanethiol on a Au(111) surface prepared in 1 mM ethanol solutions at -20, 5, 25, 60, and 78 degrees C was examined by scanning tunneling microscopy. The higher the temperature of the solution, the larger the size of the well-ordered domain with the (root 3x root 3)R30 degrees structure. The number of the vacancy islands (VIs) of the gold surface decreased while the total area of the VIs was constant, indicating that the VIs underwent ripening.