Investigation of Optical and Electrical Properties of Laser Deposited CdS Thin Films to be used in Photoelectric Applications

Inhaltsverzeichnis (Table of Contents)

• Chapter 1: Introduction
  • 1.1 Literature Survey
  • 1.2 Theoretical Background
    • 1.2.1 Film Preparation Techniques
    • 1.2.2 Physics of Laser Deposition
    • 1.2.3 The Laser Deposition Process
      • 1.2.3.a Laser-Target Interaction
      • 1.2.3.b Plume Expansion
      • 1.2.3.c Film Deposition
    • 1.2.4 Theoretical Consideration on Microstructure Properties using Diffraction Data
  • 1.3 Reflectance and Transmittance of a Single Absorbing Film on a transparent Substrate
  • 1.4 Energy Band of Semiconductors
  • 1.5 Photoconductivity
    • 1.5.1 Photoconductivity in Semiconductors
    • 1.5.2 Absorption of Light in Semiconductors
    • 1.5.3 Spectral Response of Photoconductivity
    • 1.5.4 Conduction Mechanisms
• Chapter 2: Experimental Techniques and Measurements
  • 2.1 Material Under Investigation
  • 2.2 Preparation of Thin Film Samples
  • 2.3 Main Components of the Deposition Setup
  • 2.4 Plasma Plume and Spectral Lines Measurements
  • 2.5 Film Characterization
    • 2.5.1 Determination of Film Thickness
    • 2.5.2 Structural Study of CdS Thin Films
    • 2.5.3 Film Transmittance and Reflectance
    • 2.5.4 Determination of Optical Constants of CdS Thin Film
    • 2.5.5 Design and Measurements of Film Spectral Response
    • 2.5.6 Measurements of Electrical Properties
• Chapter 3: Results and Discussion
  • 3.1 Structure Identification of CdS
  • 3.2 Optical Properties of CdS Thin Films
  • 3.3 Electrical Properties of CdS Thin Films

Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)

This thesis investigates the optical and electrical properties of laser-deposited CdS thin films for photoelectric applications. The primary objective is to characterize these properties and understand the relationships between the film's microstructure, its optical behavior, and its electrical conductivity.

• Laser Deposition of CdS Thin Films
• Optical Properties (Transmittance, Reflectance, Absorption)
• Electrical Properties (Conductivity, Dielectric Constant)
• Microstructure Characterization (XRD, SEM)
• Photoconductivity in CdS Thin Films

Zusammenfassung der Kapitel (Chapter Summaries)

Chapter 1: Introduction: This chapter provides a comprehensive overview of the existing literature on CdS thin films and their applications, establishing the context for the research. It delves into the theoretical background of laser deposition, explaining the process from laser-target interaction to film deposition, emphasizing the relevant physics. The chapter also covers theoretical considerations on microstructure properties using diffraction data, the optical properties of thin films (reflectance and transmittance), the energy band structure of semiconductors, and photoconductivity mechanisms in semiconductors, laying the foundation for the experimental work and analysis in subsequent chapters. The detailed explanation of photoconductivity mechanisms is especially crucial for understanding the later experimental results regarding the photoelectric applications of the CdS thin films.

Chapter 2: Experimental Techniques and Measurements: This chapter meticulously details the experimental methodologies employed in the thesis. It outlines the preparation of the CdS thin films via laser deposition, describing the cleaning of substrates and the setup of the deposition system. The characterization techniques used are thoroughly explained, including interferometric and envelope methods for thickness determination, X-ray diffraction (XRD) and scanning electron microscopy (SEM) for structural analysis, techniques for measuring transmittance and reflectance, and methods for determining the optical constants. Further, the chapter explains the design and measurement of the film's spectral response and the methods for measuring the electrical properties (AC resistance and dielectric measurements), ensuring the reproducibility and understanding of the experimental results presented in Chapter 3.

Chapter 3: Results and Discussion: This chapter presents and discusses the results obtained from the experimental investigations. It starts by analyzing the structural properties of the CdS thin films, using X-ray diffraction data to identify the crystal structure and determine crystallite size and microstrain. The optical properties of the films are comprehensively analyzed, focusing on the spectral distributions of transmittance, reflectance, absorption index, refractive index, and absorption coefficient. Dispersion parameters are extracted and discussed, providing a detailed picture of the optical behavior. The chapter also includes an analysis of the plasma plume characteristics and spectral profiles during the deposition process, providing insight into the deposition mechanism. Finally, the electrical properties, specifically AC conductivity and dielectric constant, are presented and interpreted, completing the comprehensive characterization of the CdS thin films in relation to their potential for photoelectric applications. The correlations between the structural, optical, and electrical properties are critically examined, offering a complete picture of the behavior of the materials and their relevance to the proposed applications.

Schlüsselwörter (Keywords)

CdS thin films, laser deposition, photoelectric applications, optical properties, electrical properties, microstructure, X-ray diffraction, scanning electron microscopy, transmittance, reflectance, absorption coefficient, photoconductivity, AC conductivity, dielectric constant.

Häufig gestellte Fragen

What is the purpose of the text about CdS thin films?

The text provides a comprehensive language preview intended for academic use, specifically for analyzing themes related to CdS thin films in a structured and professional manner. It includes the title, table of contents, objectives and key themes, chapter summaries, and keywords.

What topics are covered in the table of contents?

The table of contents outlines the structure of the thesis, covering topics such as: Introduction (Literature Survey, Theoretical Background, Film Preparation Techniques, Physics of Laser Deposition, Laser Deposition Process, Theoretical Consideration on Microstructure Properties using Diffraction Data, Reflectance and Transmittance of a Single Absorbing Film, Energy Band of Semiconductors, Photoconductivity), Experimental Techniques and Measurements (Material Under Investigation, Preparation of Thin Film Samples, Main Components of the Deposition Setup, Plasma Plume and Spectral Lines Measurements, Film Characterization), and Results and Discussion (Structure Identification of CdS, Optical Properties of CdS Thin Films, Electrical Properties of CdS Thin Films).

What are the objectives and key themes of the research?

The primary objective is to characterize the optical and electrical properties of laser-deposited CdS thin films for photoelectric applications and understand the relationships between the film's microstructure, optical behavior, and electrical conductivity. Key themes include: Laser Deposition of CdS Thin Films, Optical Properties (Transmittance, Reflectance, Absorption), Electrical Properties (Conductivity, Dielectric Constant), Microstructure Characterization (XRD, SEM), and Photoconductivity in CdS Thin Films.

What does Chapter 1 (Introduction) summarize?

Chapter 1 provides an overview of the existing literature on CdS thin films, the theoretical background of laser deposition, including the laser-target interaction and film deposition process. It covers theoretical considerations of microstructure, optical properties of thin films, the energy band structure of semiconductors, and photoconductivity mechanisms.

What does Chapter 2 (Experimental Techniques and Measurements) summarize?

Chapter 2 details the experimental methodologies, including the preparation of CdS thin films via laser deposition, cleaning substrates, and the setup of the deposition system. It explains characterization techniques like interferometry, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmittance and reflectance measurements, optical constants determination, spectral response measurement, and electrical properties measurement.

What does Chapter 3 (Results and Discussion) summarize?

Chapter 3 presents and discusses the results of the experimental investigations. It analyzes the structural properties of CdS thin films using X-ray diffraction, and examines the optical properties, focusing on transmittance, reflectance, absorption index, refractive index, and absorption coefficient. It also analyses the plasma plume characteristics and spectral profiles during the deposition process. Finally, it presents and interprets the electrical properties, specifically AC conductivity and dielectric constant, for the purpose of characterization of CdS thin films in relation to their potential for photoelectric applications. Correlations between structural, optical, and electrical properties are critically examined.

What are the keywords associated with this research?

The keywords include: CdS thin films, laser deposition, photoelectric applications, optical properties, electrical properties, microstructure, X-ray diffraction, scanning electron microscopy, transmittance, reflectance, absorption coefficient, photoconductivity, AC conductivity, dielectric constant.