Question

1) Describe and explain drift current and diffusion current in a PN junction in thermal equilibrium. What causes each? In which directions are the electrons, holes, electron current, and hole current flowing for each effect? What is the net current? Assume the built-in E-Field points to the left. Use a diagram. Then describe what changes when an electric field is applied, positive side on the N terminal. Describe what happens when the magnitude of that field is reversed.

2) Describe how the hot point probe uses diffusion to determine the type of semiconductor material.

Answer 1

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