| − | A [[dopant]] material, such as [[boron]], which has fewer outer shell [[electrons]] than required in an otherwise balanced crystal structure, providing a [[hole]], which can accept a free [[electron]].<ref>http://www1.eere.energy.gov/solar/solar_glossary.html</ref> | + | A [[dopant]] material, such as [[boron]], which has fewer outer shell [[electron]]s than required in an otherwise balanced crystal structure, providing a [[hole]], which can accept a free electron.<ref>http://www1.eere.energy.gov/solar/solar_glossary.html</ref> |