SEMICONDUCTOR PHYSICS

1 LECTURE NOTES ON SEMICONDUCTOR PHYSICS I I Semester S CHARVANI Assistant Professor FRESHMAN ENGINEERING INSTITUTE OF AERONAUTICAL ENGINEERING (Autonomous) Dundigal, Hyderabad - 500 043 2 SEMICONDUCTOR PHYSICS I Semester: Common for CSE / IT Course Code Category Hours / Week Credits Maximum Marks BSC101 Foundation L T P Foundation L T 3 1 - 4 3 1 Contact Classes:45 Tutorial Classes: 15 Practical Classes: Nil Total Classes: 60 OBJECTIVES: The course should enable the students to: I.

2 Enrich knowledge in principals of quantum mechanics and semiconductors. II. Develop strong fundamentals of electronic and optoelectronic materials. III. Enrich knowledge about measuring resistivity, conductivity and other parameters. IV. Correlate principles and applications of lasers and fiber optics. Module-I quantum mechanics Classes: 08 Introduction to quantum PHYSICS , Black body radiation, Planck s law, Photoelectric effect, Compton effect, De-Broglie s hypothesis, Wave-particle duality, Davisson and Germer experiment, Time-independent Schrodinger equation for wave function, Born interpretation of the wave function, Schrodinger equation for one dimensional problems particle in a box.

3 Module-II ELECTRONIC MATERIALS AND SEMICONDUCTORS Classes: 10 Free electron theory, Bloch s theorem for particles in a periodic potential, Kronig-Penney model (Qualitative treatment), Origin of energy bands, Types of electronic materials: metals, semiconductors, and insulators. Intrinsic and extrinsic semiconductors, Carrier concentration, Dependence of Fermi level on carrier-concentration and temperature, Hall effect. Module-III LIGHT- SEMICONDUCTOR INTERACTION Classes: 10 Carrier generation and recombination, Carrier transport: diffusion and drift, Direct and indirect bandgaps, p-n junction, V-I characteristics, Energy Band diagram, Biasing of a junction.

4 Photo voltaic effect, Construction and working of LED, Photo detectors, PIN, Avalanche photodiode, Solar cell. Module-IV ENGINEERED ELECTRIC AND MAGNETIC MATERIALS Classes: 07 Polarisation, Permittivity, Dielectric constant, Internal field in solids, Clausius Mosotti equation, Ferroelectricity, Piezoelectricity, Pyroelectricity. Magnetisation, Permeability, Susceptibility, Classification of dia, para and ferro magnetic materials on the basis of magnetic moment, Domain theory of ferro magnetism on the basis of hysteresis curve.

5 Module-V LASERS AND FIBER OPTICS Classes: 10 Characteristics of lasers, Spontaneous and stimulated emission of radiation, Metastable state, Population inversion, Lasing action, Ruby laser, SEMICONDUCTOR diode laser and applications of lasers. Principle and construction of an optical fiber, Acceptance angle, Numerical aperture, Types of optical fibers (Single mode, multimode, step index, graded index), Attenuation in optical fibers, Optical fiber communication system with block diagram.

6 3 Text Books: 1. Halliday and Resnik, PHYSICS -Wiley. 2. Dr. M. N. Avadhanulu, Dr. P. G. Kshirsagar, A text book of engineering PHYSICS , S. Chand. 3. B. K Pandey and S. Chaturvedi, Engineering PHYSICS Cengage learning. Reference Books: 1. J. Singh, SEMICONDUCTOR Optoelectronics: PHYSICS and Technology, McGraw-Hill Inc. (1995). 2. P. Bhattacharya, SEMICONDUCTOR Optoelectronic Devices, Prentice Hall of India (1997). 3. Online course: "Optoelectronic Materials and Devices" by Monica Katiyar and Deepak Gupta on NPTEL.

7 Web References: 1. 2. 3. 4. E-Text Books: 1. 2. 3. 4. 4 INDEX Module Contents Page I quantum mechanics 1 - 18 II ELECTRONIC MATERIALS AND SEMICONDUCTORS 19 - 39 III LIGHT- SEMICONDUCTOR INTERACTION 40 57 IV ENGINEERED ELECTRIC AND MAGNETIC MATERIALS 58 83 V LASERS AND FIBER OPTICS 84 - 98 5 MODULE-I PRINCIPLES OF quantum mechanics Introduction At the end of nineteenth century, physicists had every reason to regard the Newtonian laws governing the motion of material bodies and Maxwell s laws of electromagnetism.

8 As fundamental laws of PHYSICS . They believed that there should be some limitation on the validity of these laws which constitute classical mechanics . To understand the submicroscopic world of the atom and its constituents, it become necessary to introduce new ideas and concepts which led to which led to the mathematical formulation of quantum mechanics . That had an immediate and spectacular success in the explanation of the experimental observations. quantum mechanics is the science of the submicroscopic.

9 It explains the behavior of matter and its interactions with energy on the scale of atoms and its constituents. Light behaves in some aspects like particles and in other aspects like waves. quantum mechanics shows that light, along with all other forms of electromagnetic radiation, comes in discrete units, called photons, and predicts its energies, colors, and spectral intensities. A single photon is a quantum , or smallest observable amount, of the electromagnetic field because a partial photon has never been observed.

10 Considering the above facts, it appears difficult to accept the conflicting ideas that radiation has a dual nature, , radiation is a wave which is spread out over space and also a particle which is localized at a point in space. However, this acceptance is essential because radiation sometimes behaves as a wave and at other times as a particle as explained below: (1) Radiations including visible light, infra-red, ultraviolet, X-rays, etc. behave as waves in experiments based on interference, diffraction, etc.