Preface

This book presents a review of recent advances in ZnO-based nanomaterials and devices. ZnO as a nanomaterial has gained substantial interest in the research area of wide bandgap semiconductors and is considered to be one of the major candidates for electronic and photonic applications. ZnO has distinguished and interesting electrical and optical properties and is considered as a potential material in optoelectronic applications such as solar cells, surface acoustic wave devices, and UV emitters. ZnO's unique properties have attracted several researchers to study its electrical and optical properties. As a nanostructured material, ZnO exhibits many advantages for nanodevices. ZnO nanostructured material has the ability to absorb UV radiation. Recently, ZnO nanostructured devices have gained much attention due to their various potential applications. In this book, Chapter 1 is an introductory chapter that describes recent advances in ZnO nanomaterials and devices. Chapter 2 addresses the synthesis and characterization of ZnO nanostructures. Chapter 3 reports on the green synthesis of ZnO nanostructures. Chapter 4 introduces doped ZnO nanostructures and photovoltaic solar cell applications. Chapter 5 presents the pyrolysis of carbon-doped ZnO nanoparticles for solar cell applications. Chapter 6 discusses surface-enhanced Raman spectroscopy based on ZnO nanorods for biological applications. Chapter 7 presents anodic ZnO-graphene composite materials in lithium batteries.

**II**

**Chapter 7 113**

Anodic ZnO-Graphene Composite Materials in Lithium Batteries *by Herrera-Pérez Gabriel, Pérez-Zúñiga Germán, Verde-Gómez Ysmael,* 

*Valenzuela-Muñiz Ana María and Vargas-Bernal Rafael*

**Dr. Ahmed M. Nahhas** Professor, Department of Electrical Engineering, Faculty of Engineering and Islamic Architecture, Umm Al Qura University, Makkah, Saudi Arabia

**1**

Section 1

Introduction

Section 1 Introduction

**3**

**Chapter 1**

Devices

**1. Introduction**

**2. ZnO properties**

*Ahmed M. Nahhas*

tion due to their wide range applications.

being made based on ZnO's wide band gap [3].

**3. ZnO crystalline structure**

Introductory Chapter: Overview

of ZnO Based Nano Materials and

This chapter presents an introductory review about ZnO nanomaterials and nanodevices. ZnO as a wide band gap semiconductor has received a great attention in many research areas. This is due to the electrical, optical and structural properties of the ZnO. These properties make ZnO as one of the major contenders for many photonic applications. ZnO has distinguished electrical and optical properties. ZnO is considered as a potential contender in optoelectronic applications such as solar cells and ultraviolet (UV) emitters. The nanostructured ZnO material has many applications in the area of nano based devices. The UV light can be absorbed by the ZnO based nano material. This can be used in several optical applications. Currently, the nano structures based on ZnO materials devices have attracted atten-

ZnO is classified as a negative *(n*-type) semiconductor material as grown. ZnO is one of group 2–4 semiconductor materials. ZnO has a band gap of 3.37 eV. ZnO also has a high binding energy. The ZnO binding energy is about 60 meV [1]. The ZnO material has a high exciton binding energy and high thermal stability [2]. It also has a high optical gain [2]. These properties made ZnO as one of the most interesting materials for electronic and optoelectronic based devices. On the other hand, the ZnO's high binding energy permits the fabrication of several photonic devices with a high optical efficiency [3]. Also, the short wavelength optoelectronic devices are

ZnO is a transparent optical material suitable for the visible wavelength region [4].

ZnO normally has a hexagonal structure. The Zinc atoms are tetrahedrally coordinated to four oxygen atoms [13]. Moreover, there are two crystalline structure of ZnO. These structures are the wurtzite and the Zinc-blende. These two structures

ZnO is also one of the potential materials for optoelectronic applications [5–7]. The ZnO's characteristical properties were investigated by many research groups. That leads to the improvement of the electrical and the optical properties of ZnO. Many other properties of ZnO allow variety of applications. These applications include photovoltaics, LEDs, photodetectors, and microelectromechanical systems (MEMs) [8–12].

## **Chapter 1**
