Polymer-based doping control for performance enhancement of wet-processed short-channel CNTFETs

Abstract

The electrical transport properties of short-channel transistors based on single-walled carbon nanotubes (CNT) are significantly affected by bundling along with solution processing. We report that especially high off currents of CNT transistors are not only related to the incorporation of metallic CNTs but also to the incorporation of CNT bundles. By applying device passivation with poly(4-vinylpyridine), the impact of CNT bundling on the device performance can be strongly reduced due to increased gate efficiency as well as reduced oxygen and water-induced p-type doping, boosting essential field-effect transistor performance parameters by several orders of magnitude. Moreover, this passivation approach allows the hysteresis and threshold voltage of CNT transistors to be tuned.

Photosensitive Field‐Effect Transistors Made from Semiconducting Carbon Nanotubes and Non‐Covalently Attached Gold Nanoparticles

“…A precision source and measurement unit (SMU, Keithley 4200A‐SCS) was used for device characterization, with gate control achieved through the global back gate applying the voltage to the gold chuck. The test routines were adapted from literature and comprised output and transfer characteristics. Thereby, the transfer curves were taken starting at the lower boundary of the voltage range to the upper one and back to cope with hysteresis effects at an integration time of ≈40 ms per data point.…”

“…Nanoconjugates (or: hybrids) made from low‐dimensional carbon nanomaterials such as semiconducting single‐walled carbon nanotubes (SWCNTs) and transition metal and/or metal oxide nanoparticles (NPs) have received considerable interest in science and technology as nanoscopic solid‐state building blocks that enable such disruptive nanoelectronic sensor solutions with a high fidelity, sensitivity, and specifity . In such devices, semiconducting SWCNTs can act as a versatile channel material for nanoelectronic transistors (carbon‐nanotube field‐effect transistors: CNT‐FETs) as single or individualized carbon nanotubes (CNTs), aligned as oriented networks, or CNT superstructures in bundles, fibers and ropes, or composite network films . In this work, we outline a method for the fabrication of arrays of CNT‐FETs functionalized with gold nanoparticles as photosensitive or perspectively photochemosensitive field‐effect transistors.…”

CNTFET Technology for RF Applications: Review and Future Perspective

“…Dip-coating, incubation [59], spin-coating [60] or printing like techniques [61] are simple approaches to form randomly oriented CNT layers, inducing performance degradation though due to CNT-CNT junctions and crossings caused by random CNT orientation in the channel. Aligned CNT arrays from 'solution' on a substrate have been realized by Langmuir-Blodgett/Langmuir-Schaefer [62], [63], dielectrophoresis [61], [64]- [69] or evaporating-droplet [62], [70]- [73], approaches. Y. Joo et al have demonstrated a selfassembly process called FESA (floating evaporative selfassembly) [74] resulting in the ZEBRA process developed at Carbonics.…”

Advanced Characterization Methods for Electrical and Sensoric Components and Devices at the Micro and Nano Scales

“…As one of the many applications, we can take a closer look at CNT devices. Special cases of such are interconnects formed by vertically aligned CNTs grown by means of chemical vapor deposition (CVD), mechanically bendable conductive lines made from conductive CNTs, and horizontally aligned conductive tracks using multi‐walled CNTs (MWCNTs) as well as CNTFETs using semiconducting SWCNTs . For the first case of CNT vias, local electrical probing allowed a resistivity mapping of grown CNTs or mapping down to the individual CNT .…”

“…For the second case of assemblies of MWCNTs, conductivity measurements using CS‐AFM allow insight into the role of the local morphology represented by the preferential orientation on the nanoscale of the inkjet‐printed lines on the microscopic conductivity . For the third case of CNTFETs, the initial degree of positioning, CNT assembly and alignment, contact formation as well as the doping state of the channel‐building nanomaterial turned out to be important parameters. Particular challenges of hyperlocal electrical characterization are the variations of the environmental charge distribution both locally as well as temporally.…”