Optical Processes in Semiconductors.

2 Outubro 2019, 13:30 • José Figueiredo

Basic Optical Processes in Semiconductors: (Stimulated) absorption, spontaneous emission, and stimulated emission. Continuous excitation. Radiative recombination. Exciton recombination. Spontaneous recombination rates and generation rates. Non-radiative recombination. Optical Characterization Methods: reflection spectroscopy, photoluminescence (PL), transmission of light and absorption coefficient. A brief discussion of advanced methods of epitaxial growth. Molecular beam epitaxy. Case of study the laser diode from homojunction to current laser diode heterostructures.

(Biblio: chapter 6 of Compound Semiconductors: Physics, Technology, and Device Concepts, Ferdinand Scholz, Pan Stanford Publishing Pte. Ltd. 2018)

Semiconductor p-n junctions and metal semiconductor junctions.

30 Setembro 2019, 15:00 • José Figueiredo

Formation of a p-n junction. Drift and diffusion currents. Construction of a band diagram of a p-n junction. Contact potential. I-V characteristic of a p-n reverse biased and forward biased.  Reverse bias breakdown. Schottky contacts. Brief discussion of the Schottky diodes. Ohmic contacts.

(Biblio: chapters 3-5 of Electronic, Magnetic, and Optical Materials, Second Edition, Pradeep Fulay and Jung-Kun Lee, CRC Press Taylor & Francis Group 2017.)

Semiconductor p-n junctions and metal semiconductor junctions.

30 Setembro 2019, 14:00 • José Figueiredo

Formation of a p-n junction. Drift and diffusion currents. Construction of a band diagram of a p-n junction. Contact potential. I-V characteristic of a p-n reverse biased and forward biased.  Reverse bias breakdown. Schottky contacts. Brief discussion of the Schottky diodes. Ohmic contacts.

(Biblio: chapters 3-5 of Electronic, Magnetic, and Optical Materials, Second Edition, Pradeep Fulay and Jung-Kun Lee, CRC Press Taylor & Francis Group 2017.)

Seminário do DF: MOONS: the next ESO VLT’s multi-object spectrograph; Speaker: Alexandre Cabral

25 Setembro 2019, 14:30 • José Figueiredo

Seminário do DF - Abstract: MOONS will be the next Multi-Object Optical and Near-infrared Spectrograph for the Very Large Telescope, able to simultaneously observe 1000 targets, feeding a bunch of optical fibres which can be placed at user-specified locations on the Nasmyth focal plane using individual robotic positioners.The sub-fields thus selected are then driven by the fibres into two identical cryogenic spectrographs mounted on the Nasmyth platform of one of the ESO VLT 8 m telescopes. Such a facility will allow a veritable host of Galactic, Extragalactic and Cosmological questions to be addressed. In this seminar we will describe the instrument and its current status of development, detailing the Portuguese contribution. Speaker: Alexandre Cabral (Instituto de Astrofísica e Ciências do Espaço e Laboratório de Óptica Lasers e Sistemas – Dep. Física, Faculdade de Ciências da Universidade de Lisboa)

Seminário do DF: MOONS: the next ESO VLT’s multi-object spectrograph; Speaker: Alexandre Cabral

25 Setembro 2019, 13:30 • José Figueiredo

Seminário do DF - Abstract: MOONS will be the next Multi-Object Optical and Near-infrared Spectrograph for the Very Large Telescope, able to simultaneously observe 1000 targets, feeding a bunch of optical fibres which can be placed at user-specified locations on the Nasmyth focal plane using individual robotic positioners.The sub-fields thus selected are then driven by the fibres into two identical cryogenic spectrographs mounted on the Nasmyth platform of one of the ESO VLT 8 m telescopes. Such a facility will allow a veritable host of Galactic, Extragalactic and Cosmological questions to be addressed. In this seminar we will describe the instrument and its current status of development, detailing the Portuguese contribution. Speaker: Alexandre Cabral (Instituto de Astrofísica e Ciências do Espaço e Laboratório de Óptica Lasers e Sistemas – Dep. Física, Faculdade de Ciências da Universidade de Lisboa)