Resistive Switching Phenomenon Observed in Self-Assembled Films of Flame-Formed Carbon-TiO2 Nanoparticles.

Mario Commodo,Ettore Sarnelli,Andrea D’Anna,Patrizia Minutolo,Gianluigi De Falco,Alberto Aloisio,Marcello Campajola

doi:10.3390/ma14164672

Abstract

Nanostructured films of carbon and TiO2 nanoparticles have been produced by means of a simple two-step procedure based on flame synthesis and thermophoretic deposition. At first, a granular carbon film is produced on silicon substrates by the self-assembling of thermophoretically sampled carbon nanoparticles (CNPs) with diameters of the order of 15 nm. Then, the composite film is obtained by the subsequent thermophoretic deposition of smaller TiO2 nanoparticles (diameters of the order of 2.5 nm), which deposit on the surface and intercalate between the carbon grains by diffusion within the pores. A bipolar resistive switching behavior is observed in the composite film of CNP-TiO2. A pinched hysteresis loop is measured with SET and RESET between low resistance and high resistance states occurring for the electric field of 1.35 × 104 V/cm and 1.5 × 104 V/cm, respectively. CNP-TiO2 film produced by flame synthesis is initially in the low resistive state and it does not require an electroforming step. The resistance switching phenomenon is attributed to the formation/rupture of conductive filaments through space charge mechanism in the TiO2 nanoparticles, which facilitate/hinder the electrical conduction between carbon grains. Our findings demonstrate that films made of flame-formed CNP-TiO2 nanoparticles are promising candidates for resistive switching components.

Highlights

Flame synthesis is a very attractive method for the production of nanomaterials, being relatively inexpensive, scalable and based on a single-step process
Our findings demonstrate that films made of flame-formed carbon nanoparticles (CNPs)-TiO2 nanoparticles are promising candidates for resistive switching components
CNPs size distribution has a tail of particles with sizes smaller than 3 nm and a second mode for larger size

Summary

Introduction

Flame synthesis is a very attractive method for the production of nanomaterials, being relatively inexpensive, scalable and based on a single-step process. While combustion is a longstanding and well-established method for production of carbon materials, such as carbon black, its use in the production of new functional nanomaterial is more recent and it is continuously gaining ground. It makes available new kinds of nanoparticles, such as mixed oxides, metal salts and even pure metals, which are produced with fine and controlled characteristics [1,2]. Allows controlling precisely particle size, crystallinity, and phase purity This is attractive in the case of TiO2, whose properties are strongly influenced by these parameters. Research on TiO2 nanoparticles embedded in amorphous carbon is ongoing [19]

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