Preface

**Section 2 Engineering, Models and Applications 95**

Chapter 7 **Nanomaterials in Structural Engineering 115** Małgorzata Krystek and Marcin Górski

Corneliu Doroftei and Liviu Leontie

Marrugo

**VI** Contents

Chapter 6 **Magnetic Materials by Melt Spinning Method, Structural Characterization, and Numerical Modeling 97**

Chapter 8 **Nanostructured Oxide Semiconductor Compounds with Possible Applications for Gas Sensors 133**

Marcelo Rubén Pagnola, Jairo Useche Vivero and Andrés G.

The invention of the scanning tunneling microscope in 1981, the development of atomic force microscopy in 1984, and the discovery of fullerenes in 1985 are three major events that defined the birth of nanotechnology. These three events triggered a series of new explorations and applications of micro- and nanostructured materials, which have modified and different phys‐ ical and chemical properties compared to the same elements at larger scales. It is for this reason that the precise control of individual components in nanostructures is crucial to realizing dif‐ ferent functionalities in applications in electronics, energy-conversion devices, biotechnolo‐ gies, and other specific applications. The morphology of the nanostructures depends not only on the compatibility between their component phases but also on the mixing method and its dispersion if chemical approaches are used. On the other hand, the use of physical methods, self-assembly, and bottom-up approaches also allows bulk nanostructures to be synthesized. The micro- and macroscopic properties of the system (optical or magnetic properties, conduc‐ tivity, etc.) can vary without changing the chemical composition of the original material simply by controlling different parameters at the nanoscale of the materials.

In this book, the reader will discover the manufacture of nanostructures with current meth‐ odologies and their applications and uses in different techniques applied to engineering.

These aspects make the application and development of new composites attractive in differ‐ ent technologic fields, improving performance parameters in equipment with respect to en‐ ergy savings. In addition, new and improved technological applications are being discovered in hitherto unthinkable fields of science.

This book is divided into the following parts:

Part 1: Engineering: Techniques and Processes.

Part 2: Engineering: Models and Applications.

This collection of articles presents a set of excellent studies using state-of-the-art methodolo‐ gies by professional researchers from different countries in the most diverse areas of knowl‐ edge and makes the book an excellent tool for those interested in looking for the latest progressions in the topic of nanotechnology.

The editor and coeditors thank Ivana Glavic, the Author Service Manager Intech Open, for her help in the production of this book.

## **Prof. Dr.Ing. Pagnola Marcelo**

University of Buenos Aires National Council of Scientific and Technical Research Institute of Technology and Engineering Sciences "Ing. Hilario Fernández Long" (INTECIN) Buenos Aires, Argentina

> **Jairo F. Useche and Andrés G. Marrugo** Universidad Tecnológica de Bolívar, Colombia

**Section 1**

**Engineering, Techniques and Processes**

**Engineering, Techniques and Processes**

**Chapter 1**

film

ALD process. A

**Provisional chapter**

**The Atomic Layer Deposition Technique for the**

**The Atomic Layer Deposition Technique for the** 

DOI: 10.5772/intechopen.78937

Atomic layer deposition (ALD) is a standard technique employed to grow thin-film oxides for a variety of applications. We describe the technique and demonstrate its use for obtaining memristive devices. The metal/insulator/metal stack is fabricated by means

and a Ti electrode. Enhanced device capabilities (forming free, self-limiting current, non-crossing hysteretic current-voltage features) are presented and discussed. Careful analysis of the stack structure by means of X-ray reflectometry, atomic force microscopy, and secondary ion mass spectroscopy revealed a modification of the device stack from

new deposition process and the model deduced from impedance measurements support our hypothesis: the role played by ozone on the previously deposited Ti layer is found to determine the overall features of the device. Besides, these ALD-tailored multifunctional devices exhibit rectification capability and long enough retention time to deserve their use as memory cells in a crossbar architecture and multibit approach, envisaging other

**Keywords:** atomic layer deposition, nonvolatile memory, forming free memristive device, complementary resistive switching cell, redox-based resistive random access

/Ti/SiO2

layer which is addressed for the use of the ozone precursor in the HfO2

, deposited on top of a highly doped Si substrate with an SiO2

/Si. Analytical studies unravel an oxidation of the Ti

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

**Fabrication of Memristive Devices: Impact of the**

**Fabrication of Memristive Devices: Impact of the** 

**Precursor on Pre-deposited Stack Materials**

**Precursor on Pre-deposited Stack Materials**

Cynthia P. Quinteros, Alex Hardtdegen,

Cynthia P. Quinteros, Alex Hardtdegen,

Pablo Levy

**Abstract**

of ALD-grown HfO2

the intended sequence, HfO2

potential applications.

memory, ReRAM

Pablo Levy

Mariano Barella, Federico Golmar, Félix Palumbo,

Mariano Barella, Federico Golmar, Félix Palumbo, Javier Curiale, Susanne Hoffmann-Eifert, and

Javier Curiale, Susanne Hoffmann-Eifert and

Additional information is available at the end of the chapter

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.78937

#### **The Atomic Layer Deposition Technique for the Fabrication of Memristive Devices: Impact of the Precursor on Pre-deposited Stack Materials The Atomic Layer Deposition Technique for the Fabrication of Memristive Devices: Impact of the Precursor on Pre-deposited Stack Materials**

DOI: 10.5772/intechopen.78937

Cynthia P. Quinteros, Alex Hardtdegen, Mariano Barella, Federico Golmar, Félix Palumbo, Javier Curiale, Susanne Hoffmann-Eifert and Pablo Levy Cynthia P. Quinteros, Alex Hardtdegen, Mariano Barella, Federico Golmar, Félix Palumbo, Javier Curiale, Susanne Hoffmann-Eifert, and Pablo Levy

Additional information is available at the end of the chapter Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.78937

#### **Abstract**

Atomic layer deposition (ALD) is a standard technique employed to grow thin-film oxides for a variety of applications. We describe the technique and demonstrate its use for obtaining memristive devices. The metal/insulator/metal stack is fabricated by means of ALD-grown HfO2 , deposited on top of a highly doped Si substrate with an SiO2 film and a Ti electrode. Enhanced device capabilities (forming free, self-limiting current, non-crossing hysteretic current-voltage features) are presented and discussed. Careful analysis of the stack structure by means of X-ray reflectometry, atomic force microscopy, and secondary ion mass spectroscopy revealed a modification of the device stack from the intended sequence, HfO2 /Ti/SiO2 /Si. Analytical studies unravel an oxidation of the Ti layer which is addressed for the use of the ozone precursor in the HfO2 ALD process. A new deposition process and the model deduced from impedance measurements support our hypothesis: the role played by ozone on the previously deposited Ti layer is found to determine the overall features of the device. Besides, these ALD-tailored multifunctional devices exhibit rectification capability and long enough retention time to deserve their use as memory cells in a crossbar architecture and multibit approach, envisaging other potential applications.

**Keywords:** atomic layer deposition, nonvolatile memory, forming free memristive device, complementary resistive switching cell, redox-based resistive random access memory, ReRAM

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
