In theory, CNTFETs are more efficient than silicon FETs: CNFETs require less energy to turn them on and off, and the slope between on/off states is steeper.
This factor, combined with better heat tolerance, could theoretically allow carbon nanotube transistors to be packed more densely together,[2] which in turn could reduce material and electrical losses.
But CNTFETs cannot (yet) be mass manufactured, and therefore carbon nanotube processors cannot either, and both are currently limited to research facilities where they are manually assembled.
In 2013, a team of researchers at Stanford University refined the technique discovered at IBM such that misaligned nanotubes could be destroyed on the wafer, leaving only the aligned ones intact.
[1] In 2019, a team at the Massachusetts Institute of Technology in cooperation with engineers from Analog Devices created a 16-bit programmable processor with nearly 15,000 carbon nanotube transistors.