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The effective mass

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The effective mass

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    1. The effective mass Conductivity effective mass determines mobility. Density of states effective mass determines NC Cyclotron effective mass can be measured directly

    2. Electron in a periodic potential Why does the semiconductor industry use single crystal material (when possible) ?

    3. Electrons are not scattered by a periodic potential move with a constant velocity as in vacuum !

    4. Electron in vacuum

    5. Dispersion

    6. Electron in vacuum

    7. Electron in a periodic potential

    8. Electron in a 3D periodic potential

    13. Expansion of E(kx,ky,kz) near a minimum value E0= E(kx0,ky0,kz0)

    14. Expansion of E(kx,ky,kz) near a minimum value E0= E(kx0,ky0,kz0)

    16. In the coordinate system in which the effective mass tensor is diagonal

    17. Acceleration due to an electric filed (F)

    18. Effective mass tensor valid near E(k) minima and maxima only

    19. Constant energy surfaces in crystal momentum space cookies

    21. Constant energy surfaces near a minimum are ellipsoids

    22. Constant energy surfaces in Si and Ge near a minimum are ellipsoids of revolution

    23. Acceleration of an electron near an energy minimum in silicon

    24. Electron transport effective mass in silicon and germanium

    25. Homework competition find a shorter way to prove this equation for germanium than given in last years home exam

    26. The spherical case - Electrons in GaAs Holes in Si, Ge, GaAs

    27. Cyclotron resonance effective mass

    28. Cyclotron resonance effective mass to be shown in the tutorial

    29. Cyclotron resonance effective mass to be shown in the tutorial

    30. Density of states effective mass

    31. Density of states

    32. Example: density of states of hydrogen gas

    33. Density of states of solids

    34. Density of electrons in an energy band

    35. Density of holes in an energy band

    36. Approximation for the Fermi Dirac distribution for E-Ef>3KT

    37. Density of electrons in an energy band

    38. Density of states of solids in K space

    39. The density of states in an energy interval is proportional to the volume in K space between two constant energy surfaces

    41. Volume of an ellipsoid

    42. Volume of a constant energy (E) ellipsoid

    43. Density of states near a conduction band minimum or valence band maximum, and the definition of the density of states effective mass

    44. Conduction band density of states effective mass

    45. Valence band density of states effective mass

    46. Summary Conductivity effective mass determines mobility. Density of states effective mass determines NC Cyclotron effective mass can be measured directly

    47. Elective home exercise Derive conductivity and density of states effective mass for holes.

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