Study on tunneling current through barrier height using scanning tunneling microscopy

The electrical properties of viologen derivatives were studied of the tunneling current characteristics on the length of the viologen derivatives using self-assembling techniques and ultra high vacuum scanning tunneling microscopy (UHV-STM). The current-voltage (I-V) and differential conductance (dl/dV-V) characteristics were measured while the electrical properties of the formed monolayer were scanned by using a scanning tunneling spectroscopy (STS). Also, we investigated to study electrons movement which is caused by height variation because we can see the organic materials barrier height and STM tip by organic materials energy gap (Eg). The total effective barrier height Phi of viologen derivatives VC₈SH, VC₁₀SH, HSC₈VC₈SH, and HSC₁₀VC₁₀SH SAMs were calculated to be 1.076 eV, 1.86 eV, 1.85 eV, 2.28 eV, respectively.