What does donor doping do to the Fermi level?

• Pulls it down away from the band
• Lifts it up
• Removes it entirely

What raises the carrier count?

• Smaller gap or more warmth
• A larger gap and deep cold
• Painting the sample red

A p-n junction lets current through one way and blocks the other.

Circle one:   True   False

Acceptor doping pulls the Fermi level down. Which carrier dominates?

• Holes
• Electrons
• Photons

Where does the built-in field come from?

• A battery hidden inside
• The field falls from the sky
• Charges left behind

A forward push flattens the field. What happens?

• Current stops fully
• Current flows
• The junction melts

A student says heat always kills conduction in semiconductors. What is backwards?

• Warmth lifts carriers
• Cold always conducts better
• Gaps forbid all carriers

A junction passes equal current both ways. Diagnose it.

• Too much rectifying field
• The wires are too short
• No field, doped alike