Experimental characterization of temperature‐dependent electron transport in single‐wall multi‐tube carbon nanotube transistors

Abstract

Current–voltage, radio‐frequency (RF) and noise characteristics of single‐wall multi‐tube carbon nanotube (CNT) transistors were measured at cryogenic temperatures. Compared to an ambient temperature (Ta) of 300 K, only a slight drain current increase at Ta = 77 K was observed. In addition, a weak dependence of the maximum value of the current gain cut‐off frequency (fT) on Ta was obtained, indicating that fT is rather limited by the device intrinsic quantum and extrinsic capacitances than by an improved mobility due to reduced optical phonon scattering at low Ta. A noise analysis of the devices at Ta = 10 K reveals that the noise factor (NF) improvement at very low temperatures is related to the reduced Nyquist noise of all resistive transistor noise contributors. Since the main noise source in CNTFETs is the shot noise, NF remains comparatively high even at Ta = 10 K. Photo of the CNTFET embedded in RF pads (left) and schematic layout of the CNTFET (right). (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

CNTFET Technology for RF Applications: Review and Future Perspective

“…CNTs exhibit a much higher carrier mobility than 2D transition metal dichalcogenide materials (such as MoS 2 ), thus allowing to build transistors with much higher operating frequencies and current drive capability. Compared to incumbent bulk material (such as silicon and In(Ga)As), the saturation velocity is at least a factor two higher and scattering is exclusively limited to ±180°, resulting in a higher current carrying capability (e.g., [1], [2]), temperature stability and electrothermal ruggedness [3] as well as in lower power dissipation and thermal noise [4]. Furthermore, CNTs enable to easily build chemical, biological and irradiation (e.g., THz) sensors with superior detectivity (e.g., [5], [6]).…”

In Situ Synthesis of CNTs/Cu Nanocomposites and the Electronic Transport Properties

“…In real applications, the CNTs’ composites in certain arrangements, e.g., arrays, sheets, and yarns, are mostly required. Nevertheless, the physical properties of these bulk composites were significantly diminished with respect to individual CNTs . Several methods have been suggested to improve the properties of bulk CNTs’ materials by chemical or metallic doping.…”

“…Nevertheless, the physical properties of these bulk composites were significantly diminished with respect to individual CNTs. [11,12] Several methods have been suggested to improve the properties of bulk CNTs' materials by chemical or metallic doping. Numbers of metallic elements such as Cu, Cr, Au, Ag, or Al have been applied to combine with CNTs, among them Cu seems to be more excellent due to its lower cost, higher electric conductivity, better thermal conductivity, and antimicrobial activity.…”

High frequency noise of epitaxial graphene grown on sapphire

“…Microwave noise technique is also an useful tool to investigate hot‐electron transport properties in semiconductors 6, 7. Noise measurements were performed on carbon nanotubes 8, 9 and, recently, on graphene 10–13.…”