
Spectroscopy of semiconductors and dielectrics.
A.V.Chernenko
Annotation
Electrons in an ideal solid and bandgap formation. Adiabatic approximation. Singleelectron picture: HartreeFock approximation. Effective masses, concept of positively charged holes. Crystal and band structure of silicon, germanium and gallium arsenide. Interband transitions and optical properties of semiconductors. Twophoton transitions. Optical properties of metal in a DrudeLorentz model. Excitons in solids. Tight binding and Frenkel excitons. WannierMott excitons. Effect of external static fields on exciton spectra. Retardation effects and a spatial dispersion in excitonic resonances. Impurity states in dielectrics and semiconductors. Optical orientation of electron and exciton spins in semiconductors. Spinlattice and spinspin relaxation. Twodimensional semiconductor structures. Size quantization in lowdimensional systems. Quantum Hall effect.

Electrons in an ideal solid and bandgap formation. Born–Oppenheimer (adiabatic) approximation. Singleelectron picture: HartreeFock approximation.

General properties of an electron in a periodic potential. Effective masses. Concept of positively charged holes. The LuttingerKohn Hamiltonian. (k•p) approximation and effective masses in semiconductors.

Crystal and band structure of common semiconductors: silicon, germanium, gallium arsenide.

Interband transitions and optical properties of semiconductors. General insight onto interband transitions: electronradiation interaction, quantum theory of optical transitions in semiconductors. Connection with optical constants for an example of Lorentz oscillators. Dielectric function; coefficients of absorption, extinction and reflection; refraction index. KramersKronig relations. Oscillator strength and a number of optically active electrons. Sum rules.

Analytical properties of optical constants near critical points in a (joint) density of states (Van Hove singularities, critical points of maximum, minimum, saddlepoints). Cases of 3D, 2D, 1D.

Twophoton transitions and corresponding optical constants. Nonlinear optical phenomena: stimulated Brillouin scattering, harmonics generation, selffocusing.

Optical transitions in an external magnetic field. Landau oscillator and diamagnetic quantization of an electron energy spectrum. Magnetooptical oscillations in absorption spectra of semiconductors. Magnetooptical phenomena (Faraday, Cotton–Mouton and Kerr effects). Franz–Keldysh effect in an electric field.

Optical properties of metal in a DrudeLorentz model. Plasma oscillations and plasma edge. Damping of plasma oscillations (Landau damping). Lowfrequency properties of a normal metal.

Excitons in solids. Tight binding and Frenkel excitons. Longitudinal and Transverse Excitons.

Hydrogenlike (WannierMott) excitons. Effective mass approximation for Mott excitons.

Effect of external static fields on exciton spectra: excitons in an electric field, in a magnetic field. Diamagnetic excitons (a strong magnetic field case).

Retardation effects and a spatial dispersion in excitonic resonances. Exciton polaritons, 2Dpolaritons in microcavities. Surfaceplasmon polaritons.

Donor and acceptor states in semiconductors. Shallow and deep levels of impurities. Donoracceptor pairs and related optical recombination. Bound exciton complexes.

Optical orientation of electron and exciton spins in semiconductors. Spinlattice and spinspin relaxation. Optical detection of spinoriented charge carriers and excitons.

Twodimensional semiconductor structures: MOSFETs, heterstructures (quantum wells, superlattices and quantum dots).

Size quantization in lowdimensional systems. Twodimensional excitons.
