Low-frequency noise in individual carbon nanotube field-effect transistors with top, side and back gate configurations: effect of gamma irradiation

Abstract

We report on the influence of low gamma irradiation (10(4) Gy) on the noise properties of individual carbon nanotube (CNT) field-effect transistors (FETs) with different gate configurations and two different dielectric layers, SiO2 and Al2O3. Before treatment, strong generation-recombination (GR) noise components are observed. These data are used to identify several charge traps related to dielectric layers of the FETs by determining their activation energy. Investigation of samples with a single SiO2 dielectric layer as well as with two dielectric layers allows us to separate traps for each of the two dielectric layers. We reveal that each charge trap level observed in the side gate operation splits into two levels in top gate operation due to a different potential profile along the CNT channel. After gamma irradiation, only reduced flicker noise is registered in the noise spectra, which indicates a decrease of the number of charge traps. The mobility, which is estimated to be larger than 2 × 10(4) cm(2) V(-1) s(-1) at room temperature, decreases only slightly after radiation treatment, demonstrating high radiation hardness of the CNTs. Finally, we study the influence of Schottky barriers at the metal-nanotube interface on the transport properties of FETs, analyzing the behavior of the flicker noise component.

Quantum transport in carbon nanotubes covalently functionalized with magnetic molecules

“…Noise spectroscopy on our field effect transistor devices built from pristine CNTs revealed several defect levels in the SiO 2 of our substrates. The smallest trap activation energy we found was E a = 62 meV . Temperature and bias voltage in our experiments are much too low to supply the necessary energy.…”

Impact of Tunnel-Barrier Strength on Magnetoresistance in Carbon Nanotubes

“…The spin lifetime is very likely still influenced by charge traps in the SiO 2 . Suspending the CNTs or low dose gamma irradiation, which is known to remove traps in the oxide and to improve the performance of CNT-based field-effect transistors [80], would be expected to enhance the spin lifetime. The diameter of the CNT used for the Hanle measurements was 1.5 nm, giving rise to a spin-orbit coupling strength in the order of 1 meV [81].…”

Selective Neural Deletion of the Atg7 Gene Reduces Irradiation-Induced Cerebellar White Matter Injury in the Juvenile Mouse Brain by Ameliorating Oligodendrocyte Progenitor Cell Loss

“…Cranial irradiation, even a single moderate dose, leads to massive neural stem cell death (Fukuda et al, 2004) followed by changes in cell metabolism, the cellular microenvironment, cell proliferation, and tissue shape as well as long-term cognitive impairments and growth reduction (Sydoruk et al, 2014; Walenta and Mueller-Klieser, 2016). Our previous results showed that selective Atg7 deficiency reduced neural stem cell death at 6 h after irradiation.…”