Extrinsic (n-type & p-type) — Practice Quiz

Question 1

Silicon doped with phosphorus becomes:

Accepted Answer

n-type (P has 5 valence electrons; one extra)

Answer

p-type

Answer

Insulating

Answer

Conducting like a metal

Question 2

Majority carriers in a p-type semiconductor are:

Accepted Answer

Holes

Answer

Electrons

Answer

Equal electrons and holes

Answer

Photons

Question 3

If n-Si has N_D = 10¹⁶/cm³ donors (all ionized), minority carrier (hole) concentration:

Accepted Answer

~2.25 × 10⁴/cm³

Answer

~10¹⁶

Answer

~10¹⁰

Answer

Zero

Question 4

Why does even tiny doping change conductivity so dramatically?

Accepted Answer

Doping levels are tiny but carrier increase is huge compared to n_i

Answer

Doping atoms are much heavier

Answer

Doping shifts E_g

Answer

It dissolves the crystal

Question 5

An n-type semiconductor is electrically:

Accepted Answer

Neutral overall (donor ions balance donated electrons)

Answer

Negatively charged overall

Answer

Positively charged

Answer

Depends on doping