Energy band gap and transport mechanism of silsesquioxane LB film containing dendric core

We have used hybrid material between dendritic core and phenyl group containing silsesquioxane (G1-3Ph). Electrical properties and charge transport mechanism of G1-3Ph was investigated. G1-3Ph monolayer was achieved by the Langmuir-Blodgett (LB) method. The phase transition was investigated by π-A isotherm of G1-3Ph repeatedly five-cycles at the air-water interface. The monolayer was deposited onto highly oriented pyrolytic graphite (HOPG) substrates via Y-type deposition at surface pressure 5.5 mN/m. We measured morphologies and the I-V curve of G1-3Ph LB film using scanning tunneling microscopy (STM). The conductivity from 100 to 250 mV is about 3.32 x10-15, 4.55 × 10^-14, 1.86 × 10^-13, 2.27 × 10^-13 S/cm, respectively. Schottky barrier is about 1.106, 1.063, 1.025 and 1.015 eV, respectively. From the result, G1-3Ph was shown an insulating property. Fowler-Nordheim plot of G1-3Ph by I-V curves investigated transport mechanism of charge. We obtained the dominant tunneling in high-voltage region by Fowler-Nordheim plot.