Semiconductors

Tárgy adatok (2018-19 Fall Semester)

In charge of the course: Dr. Ferenc Simon

Department: BME Department of Physics

Code: BMETE11MF26

Type: An optional course of the BME TTK physics MSc studies

Requirements: 2/0/0/V/3

Language: English

Prerequisites: Fundamentals of solid state physics (BMETE11AF05)

Other expectations: A firm knowledge in electrodynamics, quantum mechanics, and solid state physics

Evaluation: oral exam (can be optionally in Hungarian)

Notes of Szilvia Mucza

Exam thematics:

1. Fundamentals of semiconductors, conductivity, structure, band structure, hybridization, basic notions (bands, gap, transitino, doping, etc.).
2. Charge carriers in intrinsic semiconductors, DOS, chemical potential, conductivity in intrinsic semiconductors, the Drude model and charge carrier mobility.
3. Charge carriers in extrinsic semiconductors, energy structure and occupation of donor levels. Degenerate semiconductors. Conductivity of doped semiconductors.
4. Band structure calculation methods in semiconductors. Distinguished points of the k-space, empty lattice, quasiclassical electron approximation, the tight-binding method, the k.p model, the envelope function aproximation.
5. Transport processes in semiconductors. Length scales, wave-packet, the semiclassical approximation. The Boltzmann equation and the relaxation time approximation.
6. Solution of the Boltzmann equation in a homogeneous electric field, correspondence to the Drude model. Mechanisms of the momentum relaxation, , Matthiesen-rule, the Eliashberg-function. The Bloch-Grünneisen formula and its limiting cases.
7. Magnetotranzport in semiconductors, the classical Hall effect, magnetoresistance. Thermoelectric effects, reciprocal relations and coefficients, the Onsager relations, the Seebeck and Peltier effects, the Kelvin expression. The thermoelectric (Peltier) cooler.
8. Diffusion effects in semiconductors, minority charge carriers, charge carrier concentration under non-equilibrium conditions and in inhomogeneous semiconductors. The charge carrier diffusion length. The p-n junction in biased and non-biased conditions.
9. Application of special diode types (avalanche breakdown, Zener effect, Esaki and Gunn diodes). Application of the Esaki and Gunn diodes. The bipolar transistor and its operation. Analogue electron tube systems.
10. Surface states, metal-semiconductor heterojunctions, the Schottky barrier. Operation of the Schottky diode. The inversion and accummulation layer. Fundamentals of JFET and MOSFET. CMOS based circuits, the NOT gate. Heterojunctions, the HEMT.
11. Optical properties of semiconductors, plasma oscillations and frequency dependent conductivity. Application of the Fresnel formula for semiconductors. Photoconductivity. Solar cells, equivaent circuits, the optimal power point. The LED and laser diode.
12. The electron spin and the spin-orbit interaction. Types of spin-orbit interaction in semiconductors. Basics of spintronics devices, the Datta-Das transistor. Spin relaxation and spin diffusion.