Question

Which type of semiconductor is formed when Arsenic is dopped with Germanium ?

Answer 1

• Pentavalent elements are those elements which have five electrons in their outershell. When pentavalent impurities like phosphorus or arsenic are added into semiconductor, four electrons form bonds with the surrounding silicon atoms leaving one electron free.
• Germanium has four valence electrons and arsenic has five valence electron. So fifth electron in arsenic is extra and conductivity is by negative charge .i.e. it is n-type semiconductivity.