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Lect8Bulk Semiconductors.ppt
- Количество слайдов: 35
Metal-Insulator-Semiconductor and Metal. Insulator-Metal Structures. Part I. Bulk semiconductors Alexander Gabovich, KPI, Lecture 8
Crystalline solids with (metals) and without (semiconductors, insulators) energy gaps
Solids made of atoms
Crystalline semiconductors
Crystalline semiconductors. A Fermi level
Crystalline semiconductors
Crystalline semiconductors Ga. As is an example of the direct-bandgap semiconductor while Ge or Si represent indirect-bandgap semiconductor. In the direct-bandgap semiconductors an electron in the conductivity band can emit a photon and recombine with a hole in the valence band. This is possible because in this process the electron does not change its momentum and the momentum of photon hν/c is extremely small.
Crystalline semiconductors Near band extrema it is often possible to make a parabolic expansion in the momentum space and to introduce an electron (minimum!) or a hole (maximum!) band mass. However, it is not always possible! Mind graphene where the dispersion is linear (Dirac spectrum). The locus of k-values corresponding to a particular energy value consists of 6 ellipsoids. Those ellipsoids are frequently called valleys. Actually, effective masses do not coincide with the free-electron mass.
Crystalline semiconductors
Crystalline semiconductors
Crystalline semiconductors
Crystalline semiconductors
Crystalline semiconductors
Crystalline semiconductors
Chemical potential, Fermi level, Fermi energy. Clarification
Crystalline semiconductors
Crystalline semiconductors
Crystalline semiconductors
Crystalline semiconductors
Crystalline semiconductors
Crystalline semiconductors
Crystalline semiconductors
Crystalline semiconductors
Crystalline semiconductors
Crystalline semiconductors
Crystalline semiconductors
Crystalline semiconductors
Crystalline semiconductors
Crystalline semiconductors
Crystalline semiconductors
Crystalline semiconductors
Inhomogeneous crystalline semiconductors
Inhomogeneous crystalline semiconductors
Inhomogeneous crystalline semiconductors
Inhomogeneous crystalline semiconductors
Lect8Bulk Semiconductors.ppt