Introduction to Organic Electronic and Optoelectronic Materials and Devices

Sam-Shajing Sun, Larry R. Dalton, Sam-Shajing Sun, Larry R. Dalton

• Publisher: CRC Press
• Year: 2016
• Print ISBN: 9781466585102
• eBook ISBN: 9781466585126
• Topic: Technology & Engineering
• Subtopic: Electrical Engineering & Telecommunications
• Index: Technology & Engineering

This book covers the combined subjects of organic electronic and optoelectronic materials/devices. It is designed for classroom instruction at the senior college level. Highlighting emerging organic and polymeric optoelectronic materials and devices, it presents the fundamentals, principle mechanisms, representative examples, and key data.

1	Introduction to Optoelectronic Materials
	Nasser Peyghambarian and M. Fallahi

CONTENTS

1.1 Introduction

1.2 Types of Optoelectronic Materials

1.2.1 Semiconductors

1.2.1.1 Basic Concepts in Semiconductors

1.2.1.2 p–n Homojunctions and Heterojunctions

1.2.1.3 Alloy Semiconductors, Quantum Wells, and Strained Quantum Wells

1.2.1.4 Light Absorption and Emission in Semiconductors

1.2.1.5 Semiconductor LEDs and Lasers

1.2.2 Optical Glass

1.2.3 Electro-Optic Materials

1.2.4 Organic and Polymeric Materials

1.3 Waveguiding Principles for Optoelectronic Materials

1.3.1 Waveguiding in Semiconductors

1.3.2 Waveguiding in Glass–Ion-Exchange Glass and Optical Fibers

1.3.3 Waveguiding in EO Materials Like LiNbO₃

1.3.4 Silica-on-Silicon Waveguides

1.3.5 Waveguiding in Organic Materials

1.4 Challenges and Recent Developments

1.4.1 Material Fabrication and Compatibility

1.4.2 Heterogeneous Integration

Exercise Questions

List of Abbreviations

References

Abstract: This chapter summarizes the principles of optoelectronic materials. Four classes of materials, including inorganic semiconductors; glassy materials; electro-optic crystals, such as lithium niobate (LiNbO₃); and organic and polymeric materials, are reviewed. Waveguiding approaches in these four classes of materials are also reviewed and some current examples provided. Finally some of the challenges in optoelectronic materials including compatibility issues, hybrid materials, and integration between different types of materials are discussed.

1.1 INTRODUCTION

Since the early 1980s the field of integrated optics and optoelectronics has experienced very rapid growth. Today optical technologies are extensively used in a wide range of applications such as telecommunications, medical, and security systems. Lasers and other photonic components are the key elements and are the focus of major research. The quest for higher performance, lower cost, and complex functionality has been the main motivation. Inorganic materials in general and semiconductors in particular play key roles in these developments. Among various inorganic materials, semiconductors have experienced tremendous developments because of their unique band structures, which give them superior electrical and optical properties suitable for a range of electronics, and passive and active optical elements. While the integration of photonics and electronics on the same chip has been the focus of major efforts, success has been somewhat limited owing to material and processing incompatibility. Heterogeneous integration combining organic and inorganic materials seems to be a promising approach to bypass these limitations. This chapter is dedicated to the fundamentals of inorganic materials and their properties used in integrated optoelectronics.

1.2 TYPES OF OPTOELECTRONIC MATERIALS

Optoelectronic components are fabricated from a broad range of materials. The material selection is based on a number of factors including optical properties (refractive index, absorption, and emission properties), electrical properties (mobility and conductivity), stability, and process compatibilities. As waveguides, the materials should exhibit very low absorption or scattering loss. Optical modulators and switches rely on materials with high electro-optic coefficients. Light-emitting diodes (LED) and lasers require materials with large radiative emission efficiencies and high gain. Finally, detectors require absorption at the desired wavelengths. On the basis of these requirements, optoelectronic materials are divided into three major categories: organics, inorganics, and hybrids. Crystalline solid materials can be divided into three categories: conductors, insulators, and semiconductors. A simple representation of the energy band structure of crystalline solid materials can illustrate their differences. In conductors the upper band is partially filled, allowing for high conductivity. In insulators the valence band is completely full and the conduction band is completely empty, and the separation between the valence band and the conduction band (energy gap) is very large (several electron volts), making them electrically insulating. In semiconductors, while the conduction band is typically empty, the energy gap separation between the conduction band and valence band is relatively small (~1 eV), allowing relatively easy transition of electrons from the valence band to the conduction band under thermal or optical excitation. Their electrical properties can be easily modified by doping, or with temperature or optical excitation. The band gap energy in semiconductors plays a key role in their electrical and optical properties.

Several base technologies have taken advantage of solid-state materials including semiconductors, insulators, and glassy materials. Examples of such technologies are silica-on-silicon, silicon-on-insulator (SOI), III–V semiconductors, ion in-diffused lithium niobate (LiNbO₃), and ion-exchanged glass. Lightwave circuits and photonic components have been fabricated using these techniques. A brief review of different types of optoelectronic materials and technologies that take advantage of them follows.

1.2.1 SEMICONDUCTORS

1.2.1.1 Basic Concepts in Semiconductors

Semiconductors are examples of crystalline solids. The potential of the crystalline lattice, W(r), has the full periodicity of the lattice, W(r) = W(r + R), with R being a vector in the direct lattice (see Figure 1.1). The periodic po...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Table of Contents
• Acknowledgments for the Second Edition
• Acknowledgments for the First Edition
• Preface to the Second Edition
• Preface to the First Edition
• Editors
• Contributors
• Chapter 1 Introduction to Optoelectronic Materials
• Chapter 2 Introduction to Optoelectronic Device Principles
• Chapter 3 Basic Electronic Structures and Charge Carrier Generation in Organic Optoelectronic Materials
• Chapter 4 Charge Transport in Conducting Polymers
• Chapter 5 Major Classes of Organic Small Molecules for Electronics and Optoelectronics
• Chapter 6 Major Classes of Conjugated Polymers and Synthetic Strategies
• Chapter 7 Low Energy Gap, Conducting, and Transparent Polymers
• Chapter 8 Conjugated Polymers, Fullerene C60, and Carbon Nanotubes for Optoelectronic Devices
• Chapter 9 Introduction of Organic Superconducting Materials
• Chapter 10 Molecular Semiconductors for Organic Field-Effect Transistors
• Chapter 11 Polymer Field-Effect Transistors
• Chapter 12 Organic Molecular Light-Emitting Materials and Devices
• Chapter 13 Polymer Light-Emitting Diodes: Devices and Materials
• Chapter 14 Organic and Polymeric Photovoltaic Materials and Devices
• Chapter 15 Organic Molecular Nonlinear Optical Materials and Devices
• Chapter 16 Polymeric Second-Order Nonlinear Optical Materials and Devices
• Chapter 17 Organic and Polymeric Third-Order Nonlinear Optical Materials and Device Applications
• Chapter 18 Organic Multiphoton Absorbing Materials and Devices
• Chapter 19 Organic and Polymeric Photorefractive Materials and Devices
• Chapter 20 Organic/Metal Interface Properties
• Chapter 21 Single-Molecule Organic Electronics and Optoelectronics
• Chapter 22 Introduction to Nonvolatile Organic Thin-Film Memory Devices
• Chapter 23 Introduction to Organic Electrochromic Materials and Devices
• Chapter 24 An Introduction to Conducting Polymer Actuators
• Chapter 25 Organic Liquid Crystal Optoelectronic Materials and Devices
• Chapter 26 Organic and Polymeric Photonic Band Gap Materials and Devices
• Chapter 27 Introduction to Polymer Photonics for Information Technology
• Chapter 28 Organic Low-Dielectric Constant Materials for Microelectronics
• Chapter 29 Self-Assembly of Organic Optoelectronic Materials and Devices
• Chapter 30 Introduction to Organic Spintronic Materials and Devices
• Chapter 31 Introduction to Organic Photo Actuator Materials and Devices
• Chapter 32 Introduction to Organic Thermoelectric Materials and Devices
• Chapter 33 Introduction to Computational Methods in Organic Materials
• Index