查看文章

The demonstration of the ability of the scanning tunneling microscope (STM) to obtain atomic resolution images under solution has resulted in an increased use of STM for electrochemical studies.'However, operation of the STM in electrochemical environments requires wen-insulated tips. The ideal tip for electrochemical studies should have a chemically and electrochemically inert insulation except for the very end of the tip. Good insulation reduces the Faradaic leakage current and, consequently, noise. The leakage current depends on such factors as tip bias, and the nature and pH oftlle solution. Glass-coated tips are commercially available. 2 The use of poly (a-methylstyrene) as an insulating material has previously been reported. 3 However, both these materials crack easily, resulting in an increased Faradaic current. In addition, glass-insulated tips cannot be used in concentrated alkali solutions. Si02 …