Multiscale Simulations of 2-D Material Ink-Based Printed Network Devices

We present a simulation study of printed transistors composed of networks of two-dimensional materials flakes based on a multiscale approach. Printed devices are modeled by generating flake distribution using a Monte Carlo method, performing ab initio density functional theory (DFT) and nonequilibrium Green’s function (NEGF) calculations to obtain flake-to-flake mobility and finally computing transport in a three-dimensional drift-diffusion scheme coupled with the electrostatics by means of the Poisson equation. The method has been applied to MoS2-based devices while investigating the impact of trap charges on the device performances as well as the mixing of MoS2with graphene, a technological option currently experimentally investigated in the literature. We will show that the presence of traps is detrimental to the OFF current, which could be the main reason for the reduced current modulation observed in experiments. Mixing MoS2with graphene can instead be considered as an option to optimize the ON and OFF current of the device.