Analysis of electronic states of DNA base molecules on Cu(111) surfaces: an STM study

摘要

For the purpose of investigating the electronic states of DNA base molecules (adenine, thymine, guanine, and cytosine), we have performed scanning tunneling microscope (STM) observation of each base molecules adsorbed on Cu(111) surfaces. Figure 1 shows two characteristic features at the positive smaple bias voltage. For cytosine, the corrugation height of the adsorbed structure were increased abruptly at V_s chemical bounds 1.5 V. However, for adenine and guanine, there was no change below 2.0 V. These result indicates that cytosine is more easily electrically reduced base molecules compared with adenine and guanine molecules. Our suggestion is essentially the same as provided in earlier studies [ref.].