半导体是一种材料，其对电流的反应方式具有某些独特的特性。它是一种对电流在一个方向流动的阻力比在另一个方向流动的阻力小得多的材料。半导体的导电性介于良导体（如铜）和绝缘体（如橡胶）之间。因此，命名为半导体。半导体也是一种材料，其导电性可以通过温度、外加电场或添加杂质的变化而改变（称为掺杂）。

虽然半导体不是发明，也没有人发明半导体，但有许多发明都是半导体器件。半导体材料的发现使电子学领域取得了巨大而重要的进步。我们需要半导体来实现计算机和计算机部件的小型化。我们需要半导体来制造二极管、晶体管和许多光伏电池等电子部件。

半导体材料包括元素硅和锗，以及化合物砷化镓、硫化铅或磷化铟。还有许多其他半导体。甚至某些塑料也可以是半导体的，这使得塑料发光二极管（LED）具有柔性，可以模制成任何想要的形状。

什么是电子掺杂(electron doping)？

根据牛顿大学的肯·梅伦多夫博士的说法，请一位科学家：

'Doping' is a procedure that makes semiconductors such as silicon and germanium ready for use in diodes and transistors. Semiconductors in their undoped form are actually electrical insulators that don't insulate very well. They form a crystal pattern where every electron has a definite place. Most semiconductor materials have four valence electrons, four electrons in the outer shell. By putting one or two percent of atoms with five valence electrons such as arsenic in with a four valence electron semiconductor such as silicon, something interesting happens. There are not enough arsenic atoms to affect the overall crystal structure. Four of the five electrons are used in the same pattern as for silicon. The fifth atom doesn't fit well in the structure. It still prefers to hang near the arsenic atom, but it is not held tightly. It is very easy to knock it loose and send it on its way through the material. A doped semiconductor is much more like a conductor than an undoped semiconductor. You can also dope a semiconductor with a three-electron atom such as aluminum. The aluminum fits into the crystal structure, but now the structure is missing an electron. This is called a hole. Making a neighboring electron move into the hole is sort of like making the hole move. Putting an electron-doped semiconductor (n-type) with a hole-doped semiconductor (p-type) creates a diode. Other combinations create devices such as transistors.

半导体史

亚历山德罗·沃尔塔在1782年首次使用了“半导体”一词。

迈克尔·法拉第是1833年第一个观察到半导体效应的人。法拉第观察到硫化银的电阻随着温度的升高而降低。1874年，卡尔·布劳恩发现并记录了第一个半导体二极管效应。布劳恩观察到，在金属点和方铅矿晶体之间的接触处，电流仅在一个方向自由流动。

1901年，第一个被称为“猫须”的半导体器件获得了专利。该设备由贾加迪斯·钱德拉·博斯发明。Cat晶须是一种用于检测无线电波的点接触半导体整流器。

晶体管是由半导体材料构成的器件。1947年，约翰·巴丁、沃尔特·布拉顿和威廉·肖克利在贝尔实验室共同发明了晶体管。

来源

• 阿贡国家实验室。“牛顿——问问科学家。”互联网档案，2015年2月27日。