Implications of Electrical Crosstalk for High Density Aligned Array of Single-Wall Carbon Nanotubes

Single-wall carbon nanotube (SWNT) based devices promise a number of applications in flexible electronics, sensing, and optoelectronics. Specifically, devices based on densely packed aligned array of SWNTs are desirable for high drive current. An unintended consequence of dense packing is a new type of electrostatic crosstalk, where a single broken SWNT-at a critical field-may initiate correlated breakdown (CBD) that produces a nanoscale fissure in the channel, and thereby, defines the density limit of the aligned-array devices. In this paper, self-consistent numerical and analytical transport models (coupled to stochastic Monte Carlo simulation) are developed to explore and interpret electrical crosstalk in aligned-array SWNTs, and guidelines for improved design are proposed. Our analysis suggests that a broken SWNT induces localized voltage drop in the neighboring SWNTs, initiating band-to-band-tunneling/impact-ionization current, and corresponding breakdown electric-field is ~23 V/μm. The fissure profile is defined by an interplay between the initial (spatial) distribution of broken SWNTs and the correlation defined by the electrostatic crosstalk. Results are summarized in a density-field phase diagram that distinguishes regions of safe operation versus random breakdown/CBD. The critical field is ultimately defined by properties of the tubes (i.e., diameter distribution, doping, and size of the breakdown spot) and the substrate (e.g., dielectric and thickness).