JAPED Home • Issue Contents

Electrically Doped Adenine Based Optical Bio Molecular p-i-n Switch with Single Walled Carbon Nanotube Electrodes
Debarati Dey and Debashis De

The photo excited electronic transmission properties of Adenine based bio molecular switch is investigated at room temperature. Landauer formalism combined with both Density Functional Theory and Non- Equilibrium Green’s Function has used to determine electronic transport characteristics of this quasi one-dimensional optical switch. Two metallic single walled carbon nanotube (4, 2) electrodes have been used to provide favorable channel for charge transfer. The charge migration from the molecular junction governs considerable difference in conducting current. This tunneling current is relatively small due to the weak coupling between the molecule and the electrodes. This bio molecular switch has operated in Coulomb-blockade regime. The bio molecule comprises its switching property between straightened (‘OFF’) to 90° twisted (‘ON’) form upon photo excitation. HOMOLUMO gaps and the spatial distribution of the molecule are discussed in detail using Hilbert space spanned based basis functions of the bio molecule. The theoretical results show that this molecule conducts up to 23mA current when it has been twisted at 90° than the straighten form. This property suggests this system has attractive prospective application in future generation optical bio molecular switch technology. Electrical doping process has been introduced for this analytical model of p-i-n switch. This process enhanced the quantum -ballistic current transmission through the scattering region of the molecule.

Keywords: Adenine, DFT, Electrical doping, NEGF, p-i-n Switch, SWCNT

Full Text (IP)