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GATE 2022 PH – Question 57

Solid State Physics · metal-semiconductor junctions · 2 marks · Multiple select

A junction is formed between a metal on the left and an n-type semiconductor on the right. Before forming the junction, the Fermi level EF of the metal lies below that of the semiconductor. Then which of the following schematics are correct for the bands and the I-V characteristics of the junction?

Candidate metal-semiconductor band diagrams and current-voltage curves.
  1. Option A in the figure
  2. Option B in the figure
  3. Option C in the figure
  4. Option D in the figure

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Show answer and explanation

Correct answer: (A) Option A in the figure; (C) Option C in the figure

Explanation

Electrons flow from semiconductor to metal, depleting the n-type side and bending its bands upward at the interface. The resulting Schottky contact rectifies as in C.