功能材料雙語(yǔ)-電功能材料-在線瀏覽
2025-03-01 15:39本頁(yè)面
【正文】 Electronic band structure(band structure)電子能帶結(jié)構(gòu) Physics of semiconductors（半導(dǎo)體物理學(xué)） band gap, also called an energy gap （ 能隙 ） or bandgap（ 帶隙 ） , is an energy range in a solid where no electron states can exist. generally refers to the energy difference (in electron volts) between the top of the valence band and the bottom of the conduction band in insulators and semiconductors. (2) Band Gap（帶隙） (3) Forbidden Band（ 禁帶 ） energy gap should be the energy difference between two different energy band. for example conducting band and valence band. However, energy in between the two band is allowed. Forbidden band do not allow any energy resident in it (4) Valence Band（ 價(jià)帶 ） In solids, the valence band is the highest range of electron energies in which electrons are normally present at absolute zero temperature. On a graph of the electronic band structure of a material, the valence band is located below the conduction band, separated from it in insulators and semiconductors by a band gap. the closest band beneath the band gap. In metals, the conduction band has no energy gap separating it from the valence band. (5) Empty band （ 空帶 ）： no electron is filled (7) Filled Band（滿帶） (6) Conduction Band（導(dǎo)帶 ） The closest band above the band gap ?The valence electrons are bound to（ 限制在 ） individual atoms, as opposed to conduction electrons (found in conductors and semiconductors), which can move freely within the atomic lattice of the material. The totally filled orbitals（ 軌道 ） with highest range of electron energies form valence, the empty orbital with no electrons is called the conduction band. 1ev The conductive mechanism of the semiconductor Electrons can be excited across the energy band gap (from filled band to empty gap ) of a semiconductor by various means, and leaving holes in the filled band， This process is known as electron–hole pair generation. The movement of electrons in the conduction band and holes in the filled band create current. types of semiconductor materials classified according to the position pure elements pounds solid solution 1. Elements conductor Elements conductor Intrinsic semiconductor 本征半導(dǎo)體 Extrinsic semiconductor 非本征半導(dǎo)體 pure semiconductor, no defect, the concentration of impurity is less than109 adding controlled impurities to a semiconductor to modify the conductivity ? the most mercially important of these elements are silicon （ 硅 ） and germanium （ 鍺 ） . Silicon and germanium are used here effectively because they have 4 valence electrons in their outermost shell which gives them the ability to gain or lose electrons equal
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