Reduction of Hysteresis for Carbon Nanotube Mobility Measurements Using Pulsed Characterization

TL;DR

This paper introduces a pulsed measurement method to reduce hysteresis in carbon nanotube mobility measurements, enabling more accurate characterization across various environments and temperatures.

Contribution

The paper presents a novel pulsed measurement technique and a tunneling front model to suppress hysteresis and analyze charge trapping in CNT devices.

Findings

Longer off times reduce hysteresis in CNT measurements.

Charge traps have depths of 4-8 nm on SiO2.

Method applicable to other nanoscale devices.

Abstract

We describe a pulsed measurement technique to suppress hysteresis for carbon nanotube (CNT) device measurements in air, vacuum, and over a wide temperature range (80-453 K). Varying the gate pulse width and duty cycle probes the relaxation times associated with charge trapping near the CNT, found to be up to the 0.1-10 s range. Longer off times between voltage pulses enable consistent, hysteresis-free measurements of CNT mobility. A tunneling front model for charge trapping and relaxation is also described, suggesting trap depths up to 4-8 nm for CNTs on SiO2. Pulsed measurements will also be applicable to other nanoscale devices such as graphene, nanowires, and molecular electronics, and could enable probing trap relaxation times in a variety of material system interfaces.