Effect of vacancy defects on anisotropic electronic transport behaviors of CoN₄C₂based 2D devices: a first-principles...

The strong anisotropic electronic transport properties of the single-atom-thick material CoN₄C₂monolayer hold immense importance for the advancement of the electronics industry. Using density functional theory combined with non-equilibrium Green's function systematically studied the electronic structural properties and anisotropic electronic transport properties of the CoN₄C₂monolayer. The results show that Co, N, and C single-atom vacancy defects do not change the electronic properties of the CoN₄C₂monolayer, which remains metallic. The pristine device and the devices composed of Co, N single-atom vacancy defects exhibit stronger electronic transport along the armchair direction than the zigzag direction, which exhibit strong anisotropy, and a negative differential resistance (NDR) effect can be observed. In contrast to the results mentioned above, the device with C single-atom vacancy defects only exhibits the NDR effect. Among them, the device with the N single-atom vacancy defect regime exhibits the strongest anisotropy, with anI_Z/I_Aof up to 7.95. Moreover, based on the strongest anisotropy exhibited by N single-atom vacancy defects, we further studied the influence of different sites of the N-atom vacancy on the electronic transport properties of the devices. The results indicate that N-1, N-2, N-3, N-12, N-23, N-123, N-1234, and N-12345 model devices did not change the high anisotropy and NDR effect of the device, and among them the N-1234 exhibits the strongest anisotropy, theI_Z/I_Areaches 6.12. A significant NDR effect is also observed for the electronic transport along the armchair direction in these devices. However, the current gradually decreases as an increase of the number of N defects. These findings showcase the considerable potential for integration of the CoN₄C₂monolayer in switching devices and NDR-based multifunctional nanodevices.