Ing Ind - Inf (Mag.)(ord. 270) - MI (486) ENGINEERING PHYSICS - INGEGNERIA FISICA
097604 - PHYSICS OF SEMICONDUCTORS
097512 - PHYSICS OF SEMICONDUCTOR NANOSTRUCTURES [I.C.]
097605 - SEMICONDUCTOR NANOSTRUCTURES
The course provides a conceptual framework for understanding the essential aspects on the Physics of semiconductor devices and their limitations, as well as the Physics of low-dimensional semiconductors where quantum confinement and strain effects are exploited for tailoring electronic and optical properties.
Risultati di apprendimento attesi
After completion of the course the students will know: i. the semiconductor structures and the fabrication and commercial aviability; ii. the impact of defects and impurities on semiconductors properties; iii. the new tendencies in semiconductor devices, as well as the current and upcoming applications of transparent semiconductors and oxides. iv. the basic principle of tight-binding and k-dot-p bandstructure calculations v. how to extract the main electronic and optical properties of Group IV, III-V and II-VI semiconductors from their bandstructure; vi. the relevant effects of quantum confinement on the optical and electronic properties of semiconductors; vii. the key elements of strain-engineering for bandstructure modification.
Defects in semiconductors Defects. Point defects: vacancies, Interstitials and substitutional atoms. Impurities. Experimental determinations. Dislocations: Burger vector, dislocation geometry (edge, screw, mixed, partial). Extended defects. Disorder. Shallow defects (Si, Ge and GaAs). Deep defects (Negative-U Center, EL2, DX). Jahn–Teller Effect. Surface charges and dipoles. Defects associated to the interfaces. Non-ideal p-n junction and metal/semiconductor interface (Schottky barrier).
Crystal structures and defects in transparent semiconductors Structure, defects and properties of transparent oxides and semiconductors (GaN, ZnO and TiO2). Amorphous films (IGZO). Current and upcoming applications: TFT transistors, displays, solar cells, etc.
Semiconductor bandstructures Bandstructure of group IV and compound (III-V, II-VI) semiconductors. Tight binding model of the bandstructure: implementation in MATLAB. The k-dot-p model: bandgap dependence of the effective mass. Symmetry of conduction (valence) band minima (maxima) and their effect on the selection rules for optical absorption: optical spin orientation. The effective mass approximation and the effective mass tensor. Density of states effective mass and conductivity effective mass. Cyclotron resonance measurements.
Semiconductors alloys Semiconductor alloys: the virtual crystal approximation. Case studies using the tight binding model implemented in MATLAB. Use of semiconductors alloys in multi-junction solar cells. Quantum confinement in semiconductor heterostructures Band offset in heterostructures, type I , II and III band alignment. Experimental determination of band offsets by X-ray photoelectron spectroscopy. Theoretical calculation of the band offset using the Jaros model. Quantum confinement effects in semiconductor heterostructures. The Schrödinger equation for the envelope function: energy levels and density of states in 2D (quantum wells), 1D (quantum wires) and 0D (quantum dots).
Strain engineering Lattice mismatch in heterostructures. Elastic strain in cubic semiconductors. Deformation potentials for hydrostatic and uniaxial strain. Strained silicon technology and strain effects on lasing in III-V and group IV semiconductors.
The student will benefit of a background knowledge of solid state Physics and quantum mechanics.
Modalità di valutazione
Students will be evaluated by means of oral examination. The oral exam is aimed at assessing the capability of the student to: -describe semiconductor structures and fabrication methods; discuss the limitations and tailoring of the semiconductors in term of defects and impurities; be aware of new applications of semiconductors, as well as of current and upcoming applications of transparent semiconductors and oxides. -discuss the effects of strain and quantum confinement, which give rise to certain optical/electronic properties and reach a good level of comprehension of fundamental physical phenomena in simplified systems.
Peter Y. Yu and Manuel Cardona, Fundamentals of Semiconductors: Physics and Materials Properties, Editore: Springer, Anno edizione: 2010, ISBN: 978-3-642-00710-1
Marius Grundmann, The Physics of Semiconductors: An Introduction including Nanophysics and Applications, Editore: Springer, Anno edizione: 2010, ISBN: 978-3-642-13884-3
J. Singh, Electronic and optoelectronic properties of semiconductor structures, Editore: Cambridge, Anno edizione: 2003, ISBN: 0-521-03574-0
J. H. Davies, The physics of low-dimensional semiconductors, Editore: Cambridge, Anno edizione: 1998, ISBN: 978-0-521-48491-6
Tipo Forma Didattica
Ore di attività svolte in aula
Ore di studio autonome
Laboratorio Di Progetto
Informazioni in lingua inglese a supporto dell'internazionalizzazione
Insegnamento erogato in lingua
Disponibilità di materiale didattico/slides in lingua inglese
Disponibilità di libri di testo/bibliografia in lingua inglese
Possibilità di sostenere l'esame in lingua inglese
Disponibilità di supporto didattico in lingua inglese