1. Ideal currents in a pn Junction

2. Debye length + - + - + + -

3. Debye length + - + - + + -

4. Transient sheath in ion acoustic wave experiments in a plasma

8. Approaches zero
Charge neutrality

9. MATLAB calculation

10. Review of pn junctions
reverse & forward bias

11. Metallurgical junction
Basic model p n
Metallurgical junction

12. Basic model p n E Depletion layer all mobile charges disappear- +
Depletion layer
all mobile charges disappear
due to the electric field

13. Basic model – thermal equilibrium no applied bias voltage
Thermal equilibrium implies
Fermi energies are the same.
Energy

14. Reverse biased PN junction

15. Reverse biased PN junction energy diagram

16. Forward biased PN junction- +
Electron flow
Hole flow

17. Forward biased PN junction energy diagram- +

18. Schottky barrier junction Thermal equilibrium
Energy -
Depletion width

19. Schottky barrier junction

20. Characteristics of a Schottky diode and a PN junction diode

21. Basic assumptions p n
Low injection

22. Majority carriers -- thermal equilibrium
Basic assumptions p n E - +
Majority carriers -- thermal equilibrium

23. Minority carriers -- thermal equilibrium
Basic assumptions p n
Minority carriers -- thermal equilibrium

24. Basic assumptions p n

25. Summary

26. Electron energy profile

27. Charge concentration p n
Complete ionization

28. Charge concentration p n Minority carrier concentration is related to
majority carrier concentration

29. Forward biased PN junction

30. Forward biased PN junction
Minority carriers increase
electron density in the n region

31. Forward biased PN junction
Similarly

32. Forward biased PN junction

33. Forward biased PN junction
Similar density equations result
from a reverse bias applied voltage.
Minority density will be significantly smaller.

34. Evolution of the density perturbations
Diffusion of the perturbation
Drift due to the electric field
Generation of additional perturbation
Collision lifetime
Steady-state
Neglect drift and generation

35. Evolution of the density perturbations
Minority carrier diffusion lengths

36. Evolution of the density perturbations
Minority carrier diffusion lengths

37. Currents – sum of hole and electron diffusion currents

38. Currents – sum of hole and electron diffusion currents

39. The Cowasaki gets excellent gas mileage.

41. Simple three-dimensional unit cell