Question

Angela sees a puzzle that uses a board with 20 holes drilled into it. There are 18 pegs in the holes, and the goal of the puzzle is to move the pegs by hopping them into the open holes until both holes are at one end of the board. How could Angela use the puzzle to model semiconductors?

A. as an n-type semiconductor with the pegs representing electrons and the holes representing positive charges
B. as an n-type semiconductor with the holes representing electrons and the pegs representing positive charges
C. as a p-type semiconductor with the pegs representing electrons and the holes representing positive charges
D. as a p-type semiconductor with the holes representing electrons and the pegs representing positive charges

Answer 1

The correct answer is:
C. as a p-type semiconductor with the pegs representing electrons and the holes representing positive charges

The pegs represent the electrons and the holes represent the positive charges: when a peg is moved, it can be seen as an electron moving, and this peg (the electron) occupies a new hole (so, it recombines with the hole) leaving behind a free hole.
Moreover, a p-type semiconductor has a larger concentration of holes than electrons, and the same is true for the puzzle (we have in fact 18 pairs of pegs-holes (electrons-holes), and then we have 2 free holes, so the concentration of holes is larger).