Question

Non-stoichiometrice cuprous oxide, Cu₂O can be prepared in the laboratory. In this oxide, copper to oxygen ratio is slightly less than 2:1. Can you account for the fact that this substance is p-type semiconductor.

Answer 1

The ratio is less than 2:1 in Cu₂O shows that some cuprous(Cu⁺) ions have been replaced by cupric (Cu²⁺) ions. To maintain electrical neutrality, every two Cu⁺ ions will be replaced by one Cu²⁺ ion thereby creating a’ hole. As conduction will be due to presence of these positive hole, hence it is a p-type semiconductor.