Formation of p-n junction in polymer electrolyte-top gated bilayer graphene transistor

Biswanath Chakraborty, Anindya Das and A. K. Sood∗ Department of Physics, Indian Institute of Science , Bangalore 560012, India Abstract We show simultaneous p and n type carrier injection in bilayer graphene channel by varying the longitudinal bias across the channel and the top gate voltage. The top gate is applied electrochemically using solid polymer electrolyte and the gate capacitance is measured to be 1.5 μF/cm2, a value about 125 times higher than the conventional SiO2 back gate capacitance. Unlike the single layer graphene, the drain-source current does not saturate on varying the drain-source bias voltage. The energy gap opened between the valence and conduction bands using top and back gate geometry is estimated.