Organophosphonates as model system for studying electronic transport through monolayers on SiO2/Si surfaces

We report electrical transport measurements made on alkylphosphonate self-assembled monolayers grown on nanometer-thin SiO2 on top of highly p-doped silicon. At small bias direct tunneling is characterized by a decay constant of β ≈ 0.7/carbon. At larger positive bias to the silicon (1.1–1.5 V) the current-voltage traces feature a prominent shoulder, reminiscent of a negative differential resistance. We attribute this feature to a significant reduction in trap-assisted tunneling, as supported by a simulation. Hence, organophosphonate monolayers are excellent model systems to study electrical transport through ordered structures; they also provide highly efficient electrical passivation of the SiO2/Si surface. The authors acknowledge funding by the DFG (Grant Nos. AB 35/8-1 and TO 266/2-1), the NSF (CHE-0924104), the Braunschweig International School of Metrology IGSM, and the Nanosystems Initiative Munich. Experimental and technological support by F. Meyer, C. Bork, A. Schmidt, and D. Rümmler is gratefully acknowledged.     «

We report electrical transport measurements made on alkylphosphonate self-assembled monolayers grown on nanometer-thin SiO2 on top of highly p-doped silicon. At small bias direct tunneling is characterized by a decay constant of β ≈ 0.7/carbon. At larger positive bias to the silicon (1.1–1.5 V) the current-voltage traces feature a prominent shoulder, reminiscent of a negative differential resistance. We attribute this feature to a significant reduction in trap-assisted tunneling, as supported by...     »