Analytical model for self-heating in nanowire geometries

An analytical closed form diffusive model is developed of Joule heating in a device consisting of a nanowire connected to two contacts on a substrate. This analytical model is compared to finite-element simulations and demonstrates excellent agreement over a wider range of system parameters in comparison to other recent models, with particularly large improvements in cases when the width of the nanowire is less than the thermal healing length of the contacts and when the thermal resistance of the contact is appreciable relative to the thermal resistance of the nanowire. The success of this model is due to more accurately accounting for the heat spreading within the contact region of a device and below the nanowire into a substrate. The heat spreading is achieved by matching the linear heat flow near the nanowire interfaces with a radially symmetric spreading solution through an interpolation function. Additional features of this model are the ability to incorporate contact resistances that may be present at the nanowire-contact interfaces, as well as accommodating materials with a linear temperature-dependent electrical resistivity.