|
In semiconductor physics, a donor is a dopant atom that, when added to a semiconductor, can form an n-type region. For example, when silicon (Si), having four valence electrons, needs to be doped as an n-type semiconductor, elements from group V like phosphorus (P) or arsenic (As) can be used because they have five valence electrons. A dopant with five valence electrons is also called a pentavalent impurity. Other pentavalent dopants are antimony (Sb) and bismuth (Bi). When substituting a Si atom in the crystal lattice, four of the valence electrons of phosphorus form covalent bonds with the neighbouring Si atoms but the fifth one remains weakly bonded. At room temperature, all the fifth electrons are liberated, can move around the Si crystal and can carry a current and thus act as charge carriers. The initially electroneutral donor becomes positively charged (ionised). ==See also== * Acceptor (semiconductors) * Electron donor 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Donor (semiconductors)」の詳細全文を読む スポンサード リンク
|