Solid State Physics Labatory

Specific Foundation / Core

* Familiarization with basic concepts for the description of materials properties. * Familiarization with the fundamental interaction mechanisms of external perturbations (electromagnetic radiation, static electric and magnetic field) with materials. * Direct correlation, experimental approach and application of processes discussed in the corresponding theoretical course on Solid State Physics through experimental procedures * Learning of basic materials characterization techniques: principle of operation, familiarization with the equipment, data acquisition, processing and evaluation. * Learning of basic methods for the calculation of electronic and structural properties of materials. * Practicing on the writing of lab reports that contain data evaluation and presentation of results.

1. Introduction to fundamental concepts related to the structural and electric characterization techniques. 2. “Reciprocal space and Brillouin zone”. Perceptualization of the relation between the diffraction pattern and the reciprocal space and of the diffraction pattern as a Fourier transform. Consolidation of the relation between the real and reciprocal space. Reciprocal space and Brillouin zone for the fcc, bcc, hcp, diamond, sphalerite and wurtzite structures. 3. “Electron microscopy”. Modes of operation of the electron microscope and related interactive software. Imaging with an electron microscope (magnification, resolution). Evaluation of the electron diffraction patterns of a mono- and a poly-crystalline material. Polytype identification. 4. “Study of surfaces and surface defects”. Microscopic surface imaging using the NanoEducator Scanning Probe Microscope. Qualitative and quantitative surface characterization of representative samples (e.g. surface roughness). 5. “Ι-V characteristics”. Characterization of p-n rectifying junctions by means of their current-voltage characteristics. Determination, using proper software, of the diode saturation current, ideality factor, series and parallel resistance. 6. “Conductivity measurements and Hall effect”. Characterization techniques of the electric properties of semiconducting materials and devices. Two- and four-contact resistivity measurements (Van der Pauw). Determination of the carrier type and concentration by means of the Hall measurements. 7. Introduction to fundamental concepts related to the optical and magnetic characterization. 8. “Electronic structure of the solids”. Calculation of the crystal structure and band structure of semiconductors (e.g. Si, GaN) using ab initio methods. Conduction and valence band, Brillouin zone. Calculation of the density of states and Fermi energy. Electronic configuration and bonding. 9. “Absorption and reflectivity”. Electronic transitions and absorption spectroscopy. Determination of the energy gaps of semiconductors from their visible light absorption spectra. Effect of the n-type carriers on the position of the absorption edge Reflectivity curve and color of transparent materials (using the AVANTES spectrometer). 10. “Vibrational properties of matter: Raman spectroscopy”. Molecular vibrations of polymers or other organic materials. Determination of the vibration frequency following proper fitting procedures and substance identification from the Raman spectrum. Phonons in solids: study of the effect of the type of the atoms, the symmetry and crystallinity on the vibrational mode frequency (using the AVARAMAN spectrometer). 11. “Vibrational properties of matter: FTIR spectroscopy. Vibrational spectroscopy measurement methods, mid/far IR spectroscopy using Fourier transform (FTIR), interferometers, FTIR microspectroscopy. In situ optical characterization. FTIR reflectivity and transmittance spectroscopy and material identification. Characterization of inhomogeneous materials with FTIR microspectroscopy 12. “Magnetic hysteresis loop”. Classification of magnetic materials (diamagnetic, paramagnetic, ferromagnetic). Acquisition and evaluation of the hysteresis loop of magnetic materials. Effect of temperature of the magnetization and magnetic susceptibility. 13. Overall discussion on the characterization techniques and presentation of selected student reports.

10-02-2020