Multiple choice __________ and ________ are n-type of semiconductors. Boron, germanium Silicon, germanium Alluminium, gallium Magnesium, lithium Cobalt, nickel Reveal answer Fill a bubble to check yourself B Correct answer Explanation it is correct. Silicon and/or germanium are doped with electron rich impurities to increase their electrical conductivity. Semiconductors so formed are called n-type semiconductors.