Sumários
Light Emitting Diodes. Device Structures. LED Materials. LED Output Spectrum. LED output wavelength variations. Heterojunctions.
30 Setembro 2024, 14:30 • José Figueiredo
Light Emitting Diodes. Device Structures. LED Materials. LED Output Spectrum. LED output wavelength variations. Heterojunctions.
Bibliography: SEMICONDUCTOR SCIENCE AND LIGHT EMITTING DIODES; Optoelectronics and Photonics: Principles and Practices, 2nd Edition Pearson Education
Photodetectors and light emitting diodes based on pn junctions.
27 Setembro 2024, 14:30 • José Figueiredo
The pn Junction. The pn Junction Band Diagram. The pn Junction Principles. Open Circuit. Forward Bias. Reverse Bias. Depletion Layer Capacitance. Recombination Lifetime. A direct band gap pn junction. Photodetectors and light emitting diodes based on pn junctions.
Bibliography: SEMICONDUCTOR SCIENCE AND LIGHT EMITTING DIODES; Optoelectronics and Photonics: Principles and Practices, 2nd Edition Pearson Education
The pn Junction Principles. Photodetectors and light emitting diodes based on pn junctions.
27 Setembro 2024, 13:30 • José Figueiredo
The pn Junction. The pn Junction Band Diagram. The pn Junction Principles. Open Circuit. Forward Bias. Reverse Bias. Depletion Layer Capacitance. Recombination Lifetime. A direct band gap pn junction. Photodetectors and light emitting diodes based on pn junctions.
Bibliography: SEMICONDUCTOR SCIENCE AND LIGHT EMITTING DIODES; Optoelectronics and Photonics: Principles and Practices, 2nd Edition Pearson Education
Review of semiconcutor concepts (I)
23 Setembro 2024, 15:30 • José Figueiredo
Conductors, semiconductors and dielectrics. Metals: Energy band diagrams, density of states, Fermi-Dirac function. Energy band diagrams of semiconductors: intrinsic semiconductors, valence and conduction bands, bandgap. Conduction electrons (free electrons) and holes, effective mass of electrons and holes. Thermal energy (kT). Mass action law. Conductivity due to conduction electrons and holes, electron and hole mobilities. Change in Fermi energy - Fermi energy and electrical work: effect of an applied voltage/electric field.
Bibliography: Chapter 3 of Optoelectronics and Photonics: Principles and Practices, Second Edition, S.O. Kasap, Pearson Education Limited
Conceptual Overview of Wave-Particle Nature of Light (III)
23 Setembro 2024, 14:30 • José Figueiredo
Fresnel’s equations - intensity, reflectance and transmittance for normal incidence. Goos-Hanchen Shift frustrated total internal reflection (FTIR) and optical tunnelling. Antireflection coatings, and dielectric mirrors. Dielectric mirrors and Brag reflectors. Absorption of light and complex refractive index: extinction and attenuation coefficients. Kramers-Kronig relations. Temporal and spatial coherence, bandwidth theorem (Heisenberg's Uncertainty relation for energy and time). Inteference of waves. Fabry-Perot optical resonators and etalons: cavity modes, resonance frequencies, free spectral range, spectral width (fringe width), finesse, quality factor Q. Fresnel and Fraunhofer diffraction, Huygens-Fresnel principle. Diffraction gratings. Brag diffraction condition. Resolving power of an imaging systems. Mach-Zehnder interferometer. Scattering of light – Rayleigh scattering, colour of day light sky. Photonic crystals. Bloch waves. Photonic bandgap.
Bibliography: Chapter 1 of Optoelectronics and Photonics: Principles and Practices, Second Edition, S.O. Kasap, Pearson Education Limited