A doping-free approach to carbon nanotube electronics and optoelectronics

The electronic properties of conventional semiconductor are usually controlled by doping, which introduces carriers into the semiconductor but also distortion and scattering centers to the otherwise perfect lattice, leading to increased scattering and power consumption that becomes the limiting factors for the ultimate performance of the next generation electronic devices. Among new materials that have been considered as potential replacing channel materials for silicon, carbon nanotubes (CNTs) have been extensively studied and shown to have all the remarkable electronic properties that an ideal electronic material should have, but controlled doping in CNTs has been proved to be challenging. In this article we will review a doping-free approach for constructing nanoelectronic and optoelectronic devices and integrated circuits. This technique relies on a unique property of CNTs, i.e. high quality ohmic contacts can be made to both the conduction band and valence band of a semiconducting CNT. High performance nanoelectronic and optoelectronic devices have been fabricated using CNTs with this method and performance approach to that of quantum limit. In principle high performance electronic devices and optoelectronic devices can be integrated on the same carbon nanotube with the same footing, and this opens new possibilities for electronics beyond the Moore law in the future.