Preface

**Section 4 Organic Field-Effect Transistors 123**

Chapter 8 **Field-Effect Transistors for Gas Sensing 149** Toshihiro Yoshizumi and Yuji Miyahara

> **Point‐of‐Care Testing 165** Zhihui Yi and Jonathan Sayago

**and Process 125**

**Section 5 Applications 147**

**VI** Contents

Chapter 7 **Organic Field-Effect Transistor: Device Physics, Materials,**

Chapter 9 **Transistors as an Emerging Platform for Portable Amplified**

**Biodetection in Preventive Personalized**

Jingjing Chang, Zhenhua Lin, Chunfu Zhang and Yue Hao

In 1959, Atalla and Kahng at Bell Labs produced the first successful field-effect transistor (FET), which had been long anticipated by other researchers, by overcoming the "surface states" that blocked electric fields from penetrating into the semiconductor material. Very quickly, they became the fundamental basis of digital electronic circuits. Up to this point, there are more than 20 different types of field-effect transistors, which are incorporated in various applications found in everyday's life. Based on this fact, this book was designed to overview some of the concepts regarding FETs that are currently used as well as some con‐ cepts that are still being developed.

The first section "Field-Effect Transistor Theory" provides methodologies related to carrier mobility, one of the most important parameters of field-effect transistors. Carrier mobility, also known as carrier ability to move through the crystal, further defines electrical perform‐ ances of the device. The knowledge regarding carrier mobility is very important in order to understand the physics of conduction mechanisms inside semiconductor devices, which fur‐ ther provides modeling of a single transistor and more complex circuits as well. Convenient methods for mobility measurements and conduction parameter extraction are also covered in this chapter. In addition, this section gives additional considerations of a new type of field-effect transistor with a gate and a channel on a basis of two-dimensional systems of carriers. The key point of the device is that the systems are different. In particular, they are formed in different quantum wells or valleys of the carrier spectrum.

In the section "High Electron Mobility Transistors," the focus is given to high electron mobi‐ lity transistors, which undergo intensive attention in high-speed and high-power applica‐ tions. HEMT devices are competent with traditional field-effect transistors and always replace traditional FETs due to their excellent performance at high frequencies. This chapter presents different structures of high electron mobility transistors as well as working princi‐ ples. Furthermore, some of the latest researches on HEMTs and future trends are also cov‐ ered in this section. Further, quantum mechanical phenomenon was reviewed, which induces various electrical and optical properties in low-dimensional semiconductor nano‐ structures such as high electron mobility transistors. This section is concluded with future trends in production of high electron mobility transistors, which is based on novel approach toward new materials and device structures in order to make the device more suitable for faster device operation with high frequency.

The section "Thin-Film Transistors" deals with the most common problems in production of thin-film transistors such as impact of metal-semiconductor interface, which can be further applied for other types of field-effect transistors. In this chapter, some alternatives to im‐ prove this interface are analyzed. Also, the influence of this interface on the electrical stabili‐ ty of these devices is presented.

The section "Organic Field-Effect Transistors" reviews the concepts of organic field-effect transistor physical mechanisms, materials, and fabrication process. In recent years, organic field-effect transistors have received much attention in various applications. The main effort is focused to achieve device performance with high charge carrier mobility and good stabili‐ ty. It is expected that proper combination of organic semiconductor materials and fabrica‐ tion techniques could lead to production of high-speed devices, which can be used in various applications.

In the section "Applications," some examples regarding possible applications of different types of field-effect transistors in different fields of interest, such as gas-sensitive field-effect transistors as well as concepts of biosensors based on transistor structures with relevance in the field of easy-to-use, portable, and user-friendly devices for preventive personalized medical applications and point-of-care testing, are given.

The editors hope that the publication *Different Types of Field-Effect Transistors - Theory and Applications* could be a useful tool for researchers in related areas.

> **Prof. Dr. Momčilo M. Pejović and Dr. Milić M. Pejović** University of Niš Faculty of Electronic Engineering Niš, Serbia

**Field-Effect Transistor Theory**

prove this interface are analyzed. Also, the influence of this interface on the electrical stabili‐

The section "Organic Field-Effect Transistors" reviews the concepts of organic field-effect transistor physical mechanisms, materials, and fabrication process. In recent years, organic field-effect transistors have received much attention in various applications. The main effort is focused to achieve device performance with high charge carrier mobility and good stabili‐ ty. It is expected that proper combination of organic semiconductor materials and fabrica‐ tion techniques could lead to production of high-speed devices, which can be used in

In the section "Applications," some examples regarding possible applications of different types of field-effect transistors in different fields of interest, such as gas-sensitive field-effect transistors as well as concepts of biosensors based on transistor structures with relevance in the field of easy-to-use, portable, and user-friendly devices for preventive personalized

The editors hope that the publication *Different Types of Field-Effect Transistors - Theory and*

**Prof. Dr. Momčilo M. Pejović and Dr. Milić M. Pejović**

University of Niš

Niš, Serbia

Faculty of Electronic Engineering

ty of these devices is presented.

medical applications and point-of-care testing, are given.

*Applications* could be a useful tool for researchers in related areas.

various applications.

VIII Preface
