A Study and Investigation of Structural Parameters of Vertically Aligned Carbon Nanotube Arrays as a Thermal Interface Material

Carbon nanotubes (CNTs) have high thermal conductance and the potential to be the thermal interface material (TIM) of the future. This paper presents how various structural parameters like mean height, a fractional standard deviation of height, a fractional standard deviation of space, and an outer diameter of CNT arrays affect the contact area and the tip contact resistance (TCR) between the heat sink and vertically aligned CNTs (VACNTs) using the simulation tool. The simulation tool is based on the bead-spring model, and it counts van der Waals interactions between the heat sink and VACNT. It is investigated that by changing the fractional standard deviation of height from 0 to 0.05, TCR increases from 62.26–319.52 mm²K/W. It is also observed that by changing an outer diameter from 40 and 72 Å, tip contact resistance decreases from the range of 124.68–62.26 mm²KW⁻¹ that is a decrement of 62.42 mm²KW⁻¹, and by changing an outer diameter from 40 to 400 Å, TCR decreases from 124.68–4.49 mm²KW⁻¹. These types of simulation results show that the mean height and the fractional standard deviation of space do not show a drastic change in TCR value, but the fractional standard deviation of height and the outer diameter of multi-walled CNT in VACNT are among the primary parameters which drastically change TCR value while slightly changing them.