Effect of Coulomb carrier drag and terahertz plasma instability in p+-p-i-n-n+ graphene tunneling transistor structures

Abstract

We evaluate the influence of the Coulomb drag of the electrons and holes in the gated n-and p-regions by the ballistic electrons and holes generated in the depleted i-region due to the interband tunneling on the current-voltage characteristics and impedance of the p + -p-i-n-n + graphene tunneling transistor structures (GTTSs). The drag leads to a current amplification in the gated n-and p-regions and a positive feedback between the amplified dragged current and the injected tunneling current. A sufficiently strong drag can result in the negative real part of the GTTS impedance enabling the plasma instability and the self-excitation of the plasma oscillations in the terahertz (THz) frequency range. This effect might be used for the generation of the THz radiation.

Ballistic injection terahertz plasma instability in graphene n+-i-n-n+ field-effect transistors and lateral diodes

“…As pointed out previously [18][19][20], such a situation implies the possibility of the plasma instability (see below), i.e., the self-excitation of the plasma oscillations (see, for example, [28]).…”

“…The obtained results imply that the n +i-n-n + GFETs and GLDs can be used in novel THz radiation sources. A similar instability could also occur in p +i-p-p + (including the structures based on G-multilayers with the carriers induced by the gate voltage [43] or doping) and the p + -p-i-n-n + single G-layer (i.e., GTTs [20]) or G-multilayer [44] structures with the Zener-Klein interband tunneling generation of ballistic carriers.…”

“…The high-energy ballistic electrons (BEs) [6][7][8][9][10][11][12] injected into the G-channel lead to an effective Coulomb drag of the equilibrium carriers [13][14][15][16][17] strongly affecting the device characteristics. As demonstrated recently [18,19], the Coulomb interaction of the injected BEs with the quasi-equilibrium electrons (QEs) results in the dragged electrons (DEs) in the gated Gchannel of the n + -i-n-n + graphene field effect transistors (GFETs) and the dragged holes (DH) in the p + -p-i-n-n + graphene tunneling transistors (GTTs) [20]. The drag effect is associated with the linearity of the electron and hole energy-momementum relations in G-channels and followed from the specifics of the kinematics of the carrier pair collisions [21][22][23] and can enable the plasma instability associated with the internal current amplification [14].…”