A comprehensive study on properties of Semiconductors and p-n Junction

Scientific Essay , 2012 , 8 Pages

Physics - Electrodynamics

A comprehensive study of p-n junction is necessary to design an electronic device as well as circuits. An electronic device controls the movement of electrons. The study of electronic devices requires a basic understanding of the relationship between electrons and other components of an atom. This leads to knowledge of the differences between conductors, insulators and semiconductors and to an understanding of p-type and n-type semiconductor material. p-n junction is formed by joining p-type and n-type semiconductor materials. So the concept of semiconductor, majority and minority carrier of p-type and n-type semiconductor, doping, depletion region of p-n junction, mobility and conductivity, drift and diffusion current, carrier concentration calculation and Fermi energy level is actually the comprehensive study of p-n junction.

Inhaltsverzeichnis (Table of Contents)

• Introduction
• I. What is a semiconductor?
• II. Classification of conductor, semiconductor and insulator
• III. Conductivity in Semiconductors
• IV. Types Of semiconductors
  • A. n-Type:
  • B. p-Type:
• V. Carriers
• VI. Difference In Band Structure
• VII. Carrier Properties
• VIII. State and Carrier Distribution
  • A. Density of States:
  • B. The Fermi Function:
  • C. Equilibrium Carrier Concentrations:
  • D. Formulas for n and p:
  • E. The n; and np Relation:
• IX. Carrier Concentration of Electrons
• X. Carrier Concentrations of Holes,
• XI. Position of Fermi energy level
  • A. For Intrinsic Semiconductor:
  • B. For Extrinsic semiconductor:
• XII. Basic Structure of p-n junction
• Conclusion (Fazit)
• Bibliography (Literaturverzeichnis)

Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)

This comprehensive study aims to provide a detailed understanding of semiconductors and the fundamental p-n junction, a crucial component in electronic device design. The text explores the properties of semiconductors, including their conductivity, doping, and carrier characteristics. It delves into the formation and behavior of p-n junctions, examining the concepts of depletion region, drift and diffusion currents, and carrier concentration calculations.

• Properties of Semiconductors
• Formation and Characteristics of p-n Junctions
• Carrier Concentration and Distribution
• Fermi Energy Level and its Significance
• Applications of p-n Junctions in Electronic Devices

Zusammenfassung der Kapitel (Chapter Summaries)

The introduction provides a brief overview of the importance of semiconductors and p-n junctions in electronic device design. It highlights the need for a comprehensive understanding of these concepts to effectively control the movement of electrons in electronic circuits.

Chapter I defines semiconductors as materials exhibiting conductivity between conductors and insulators. It explains how their conductivity varies with temperature and the influence of impurities. The chapter also introduces examples of semiconductor materials, such as silicon, germanium, and gallium arsenide.

Chapter II classifies solids based on their electrical conductivity, distinguishing between metals, semiconductors, and insulators. It utilizes band theory to explain the differences in their conductivity, emphasizing the role of the forbidden gap in determining the material's behavior.

Chapter III delves into the conductivity of semiconductors, focusing on the covalent bonding between atoms and the factors influencing their conductivity. It discusses the negative temperature coefficient of resistance and the impact of light excitation on conductivity.

Chapter IV explores the types of semiconductors, distinguishing between intrinsic and extrinsic semiconductors. It explains the process of doping, where impurities are added to enhance conductivity. The chapter then elaborates on n-type and p-type semiconductors, created by donor and acceptor doping, respectively.

Chapter V discusses the charge carriers in semiconductors, highlighting the role of electrons and holes in creating current flow. It explains how the breaking of bonds between atoms releases electrons and creates holes, which act as charge carriers.

Chapter VI compares the band structures of conductors, semiconductors, and insulators, emphasizing the significance of the energy gap between the conduction and valence bands. It explains how the narrow band gap in semiconductors allows for moderate charge carrier generation at room temperature.

Chapter VII examines the properties of charge carriers in doped semiconductors, including their charge, effective mass, and concentration. It discusses the concept of effective mass and its dependence on the semiconductor material and temperature.

Chapter VIII delves into the state and carrier distribution in semiconductors, focusing on the density of states and the Fermi function. It explains how these concepts are used to calculate carrier concentrations under equilibrium conditions.

Chapter IX focuses on the carrier concentration of electrons, deriving the equation for thermal equilibrium concentration by integrating over the conduction band energy. It utilizes the Boltzmann approximation to simplify the Fermi probability function.

Chapter X examines the carrier concentration of holes, deriving the equation for thermal equilibrium concentration by integrating over the valence band energy. It also utilizes the Boltzmann approximation to simplify the Fermi probability function.

Chapter XI explores the position of the Fermi energy level in intrinsic and extrinsic semiconductors. It explains how the Fermi level shifts closer to the conduction band in n-type materials and closer to the valence band in p-type materials.

Chapter XII introduces the basic structure of a p-n junction, formed by joining p-type and n-type semiconductors. It describes the diffusion of charge carriers across the junction and the formation of the depletion region.

Schlüsselwörter (Keywords)

The keywords and focus themes of the text encompass semiconductors, p-n junctions, conductivity, doping, carrier properties, carrier concentration, Fermi energy level, depletion region, drift and diffusion currents, and electronic device design. The text explores the fundamental principles of semiconductor physics and their application in the creation of electronic devices, particularly p-n junction diodes.

• Author: Umana Rafiq (Author)
• Publication Year: 2012
• Pages: 8
• Catalog Number: V278587
• ISBN (eBook): 9783656719052
• ISBN (Book): 9783656719038
• Language: English
• Tags: semiconductors, junction