Organic Electronics 1

Materials and Physical Processes

Thien-Phap Nguyen

• Editore: Wiley-ISTE
• Anno: 2021
• ISBN:
  9781119818939
• Edizione: 1
• Argomento: Technik & Maschinenbau
• Categoria: Elektrotechnik & Telekommunikation

Due to their special properties, organic semiconductors enable the development of large-area, low-cost devices, paving the way for flexible and nomadic applications that advantageously replace those made with traditional semiconductors.

This book describes the properties and deposition methods of organic semiconductors, transparent conductive materials or metals which are used in the fabrication of organic devices. The physical processes (optical, electrical and interface) that control the mechanisms in the formation and transport of the charge carriers of the materials are studied and explained in detail.

Organic Electronics 1 introduces the fundamental and applied aspects of the field of organic electronics. It is intended for researchers and students in university programs or engineering schools specializing in electronics, energy and materials.

1
Semiconductor Theory

This chapter provides a brief overview of the basic concepts of semiconductor theory with regard to particular physical characteristics that allowed the creation of electronic components that would revolutionize various technologies starting in the middle of the 20th Century. We will now describe the operation of P–N junctions, which are the essential components for the creation of electronic devices. This basic knowledge will then allow us to address physical processes in organic materials and then to understand the operation and use of devices based on new organic semiconductors.

1.1. Introduction

In electronics, the basic materials are semiconductors (SCs). They differ from metals in their dependence on the temperature of their electric characteristics. Essentially, when the temperature increases, the resistivity of metals increases, while the resistivity of SCs decreases. The theoretical contributions made by quantum mechanics allowed the electrical properties of SCs to be studied and explained based on the theory of energy bands. Unlike metals, in which the charge carriers are electrons, SCs can also carry positive charges, known as holes, that contribute to the electrical conductivity of these materials. The concentration of the carriers can also be changed by “doping”, that is, the incorporation of the selected impurities in a determined quantity. This process not only allows the conductivity of the SC to be changed, but also favors the transport of one type of charge carrier at the expense of the other. An SC is characterized as N-type if the majority of the carriers are electrons and as P-type if the majority of the carriers are holes.

The combination of an N-type and P-type SC is a P–N junction, which is the fundamental element of all traditional electronic components. The assembly of these elements, prepared with other materials, makes it possible to create components that perform special functions, and the design of the circuits with these components leads to multiple applications of various different types.

The miniaturizing of components has given rise to the field known as microelectronics, the technology for microscale component manufacturing while maintaining the same characteristics as conventional components. This new technology has significantly reduced the size of miniaturized electronic circuits, as well as certain devices that can be made portable. With the advent of integrated circuits, discrete components can now be installed on boards using a minimum amount of space an...