Chirality Dependence of Electron Transport Properties of Single-Walled GeC Nanotubes

Electron transport properties of zigzag single-walled GeC nanotubes (GeCNTs) of different chiralities have been studied by using a combined method of density functional theory and nonequilibrium Green’s function formalism. Transmission pathways at zero bias are analyzed for GeCNTs up to (8,0) chirality. The flow of electron is hindered for nanotubes of chiralities higher than (6,0), which leads to a drastic reduction in the conductance of these devices. Band structures of all five GeCNTs are calculated. The transmission coefficients are estimated for (n,0) GeCNTs (n = 4, 5, 6) at various positive and negative bias voltages within ±2.8 V. The current–voltage (I–V) curves of these systems are drawn for different bias voltages. The I–V characteristics of all three devices show negative differential resistance, which is analyzed from the transmission spectra and molecular projected self-consistent Hamiltonian states. The variations of the rectification ratio (I +/I –) with the bias voltage for (4,0), (5,0), and (6,0) GeCNTs are also reported.