Preface

The framework of this book was developed in the search for a new demand for materials that would facilitate our advanced technologies in the twenty-first century. Today, technolo‐ gy has become a ubiquitous part of our lives and consequently a critical component of all areas of our life. People wake up with checking up their emails on their smartphones and go to work in their car that has lots of sensors such as collision detection, parking assistant, lane departure warning, and so on. With the help of rapidly growing artificial intelligence tech‐ nology, a self-driving autonomous car gives you the luxury to sit back in the car seat to get to the work. These sound like science fiction or movie scenes from a Hollywood blockbuster about the future but this is happening right now. Research and development of these tech‐ nologies are moving at lightning pace, which is attributed to the semiconductor technology. After the birth of semiconductor technology in 1947, it was heavily dominated by siliconbased semiconductor technology for more than 60 years. However, the limitation of silicon technology invited a number of researchers to search for other alternatives including germa‐ nium. At the beginning of internet-of-things era (IoT), more autonomous systems were im‐ plemented in every corner of our lives and this strongly demands faster and lower power semiconductor device applications to meet our needs.

Germanium is an interesting material to explore in many applications. Although we rarely see them in our everyday life, they are embedded in many other applications where they play a critical role such as a main component of machines, tools, systems, instruments, and so on. The major applications for germanium are infrared optics, optical fibers, semiconduc‐ tor devices, catalysts, and nuclear radiation detectors. At the beginning of a postsilicon era, most experts expect developing applications with new material alternatives; in particular, germanium beyond silicon technologies would eventually lead to a new technology revolu‐ tion in the coming centuries.

In the fast-moving age of digital knowledge, it is almost impossible to follow up with all the new technologies. Furthermore, synchronized with these new technologies, a market keeps changing and transforming on a nearly yearly basis as we spend more time on our mobiles, tablets, laptops, and newly introduced gadgets. In the center of these changes, we are excit‐ ed to present this book to readers in the belief that we can contribute to the process of deep‐ ening new knowledge.

> **Prof. Sanghyun Lee, PhD** Indiana State University Terre Haute, Indiana, USA

**Chapter 1**

**Provisional chapter**

**Introductory Chapter: Advanced Material and Device**

**Introductory Chapter: Advanced Material and Device** 

The search for new semiconductor materials began with new technology requirements in the early nineteenth century [1]. One of the pivotal discoveries was silicon (Si) and germanium (Ge), by Clemens Winkler in 1886. The current semiconductor technology is mostly based on Si material to fabricate integrated circuits (ICs) in the era of high-speed Internet-of-Things (IoT). Since Si transistors of ICs have faced physical limitations due to their fundamental properties, a number of researchers are actively searching for alternatives, which reignite the active study of Ge to break through the technology roadblock. The scope of this introduction is to describe the historical background of Ge materials from ores and their application to advanced devices such as photodetectors, solar cells, spintronics, IC, etc., which are essentially semiconductor applications in all areas of our current technologies [2]. Furthermore, this chapter will discuss the opportunities and challenges of Ge materials and advanced device applications for the next technology generation. The last part of this section will outline the topic of each chapter

with some practical suggestions on how to efficiently utilize this book for readers.

Nowadays, almost 95% of all the semiconductors are fabricated on Si material. Si semiconductors began to be used in the mid-1960s. The silicon devices demonstrate better and stable properties at room temperature. Furthermore, generating high-purity silicon wafer can be relatively easily achieved by the so-called Czochralski process. This is a method of crystal growth used to obtain single crystals of semiconductors, where high-quality silicon dioxide can be grown at room temperature [3–8]. From the economic perspective, high-purity Si for

> © 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.

DOI: 10.5772/intechopen.80872

**Applications with Germanium**

**Applications with Germanium**

Additional information is available at the end of the chapter

Sanghyun LeeAdditional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.80872

**2. Elemental semiconductor material**

Sanghyun Lee

**1. Introduction**

#### **Introductory Chapter: Advanced Material and Device Applications with Germanium Introductory Chapter: Advanced Material and Device Applications with Germanium**

DOI: 10.5772/intechopen.80872
