How does a diode work - the PN Junction (with animation) | Intermediate Electronics · CircuitBread
讲解二极管的核心PN结结构，通过动画演示其工作原理，适合练习电子基础和半导体相关词汇。
In our previous tutorials, we’ve discussed the basics of semiconductors, band gap, current carriers, and its classification.
在我们之前的教程中，我们讨论了半导体的基础知识、带隙、电流载流子以及半导体的分类方法。
We learned that in order for a
我们了解到，为了实现某个目标（或让某件事发生），需要满足某些条件或步骤。
semiconductor material to be useful, it needs
半导体材料要想真正发挥作用，还需要满足某些条件（或：具备某些特性）。
to be doped with an impurity atom
被掺杂了杂质原子
and it could be a pentavalent atom to produce an n-type material or a trivalent atom to come up with a p-type material.
这种原子可以是五价原子，用于制备 n 型半导体材料；也可以是三价原子，用于制备 p 型半导体材料。
Now, if we take a small piece
现在，如果我们取一小块……
of semiconductor material and dope half of it with a trivalent atom and the other half with a pentavalent atom,
这种材料由半导体构成：其中一半掺杂了三价原子，另一半则掺杂了五价原子。
that would result in a semiconductor device with p-type and n-type portions, with a pn junction where they meet.
这样就会得到一种半导体器件，该器件包含 p 型和 n 型区域，两者在交界处形成 pn 结。
In this video, we are going to talk about this pn junction, as it is the basis for diodes.
在这段视频中，我们将讨论PN结，因为它是二极管的基础。
After doping an intrinsic semiconductor material, usually silicon, so that part of it is p-type and the other part is n-type,
通过对本征半导体材料（通常是硅）进行掺杂处理，使其一部分变为 p 型，另一部分变为 n 型后……
a pn junction is formed at the boundary between the p and n regions.
PN结是在P区和N区的交界处形成的。
In the p region, the majority carriers are holes while in the n region, the majority carriers are free electrons.
在 p 区，多数载流子是空穴；而在 n 区，多数载流子是自由电子。
When the pn junction is formed, the
当形成 pn 结时，
free electrons in the n region begin to diffuse across the junction and combine with the holes in the p region near the junction.
位于 N 区的自由电子开始穿过结区，并与位于结区附近的 P 区中的空穴结合。
This makes the n region lose free electrons and creates a layer of positive charges near the junction.
这样一来，N区会失去自由电子，并在结附近形成一层正电荷。
As the free electrons combine with the
当自由电子与……（此处内容缺失）结合时……
holes in the p region, the p region also loses holes and creates a layer of negative charges near the junction.
在 P 区中，由于空穴的流失，P 区会在结附近形成一层负电荷。
These two layers of positive and negative charges create a region where charge carriers are depleted.
这两层正负电荷共同作用，形成了一个电荷载体（即载流子）极度匮乏的区域。
This region is called, fittingly, the depletion region.
这个区域被恰当地称为“耗尽区”（depletion region）。
In reality, the depletion region is formed
实际上，耗尽区（depletion region）就是这样形成的。
in an incredibly short amount of time and its width is very thin compared to the p and n regions.
在极短的时间内，其宽度与 P 区和 N 区相比非常小。
The depletion region will continue to expand until the total negative charge in the depletion region repels any further diffusion of electrons into the p region.
耗尽区会持续扩大，直到该区域内的总负电荷强度足以阻止电子进一步向 p 区扩散。
This time, the depletion region acts as a barrier to the movement of electrons across the junction.
这一次，耗尽区起到了阻碍电子在结点处移动的作用（即成为电子流动的障碍）。
In the depletion region, there are many positive and negative charges on opposite sides, and as described by Coulomb’s law,
在耗尽区域（depletion region）中，正负电荷分别分布在区域的两侧。根据库仑定律（Coulomb’s law）的描述，……
if there’s a positive charge and a negative charge near each other, there is a force acting on these charges.
当正电荷和负电荷彼此靠近时，它们之间会产生一种作用力。
The forces between the positive and negative
正电荷与负电荷之间的相互作用力
charges in the depletion region create an electric field which blocks the free electrons from the n region to flow across the junction.
耗尽区中的电荷会产生一个电场，这个电场会阻碍来自 N 区的自由电子穿过结（junction）。
In order for the electrons to move
为了让电子能够移动
through this electric field, a certain amount
通过这个电场，会有一定的能量（或电流等）被传递。
of voltage equal to the barrier potential of the electric field must be applied across the pn junction with the proper polarity.
必须以正确的极性，在PN结上施加一个电压，该电压的大小等于电场的势垒电压。
Now, let’s try to analyze the formation of the pn junction and the depletion region through an energy diagram.
现在，让我们尝试通过能量图来分析 pn 结的形成以及耗尽区的形成过程。
The energy levels of the valence and conduction bands in an n-type material are lower than the valence and conduction bands in a p-type material.
在 n 型材料中，价带和导带的能量水平低于 p 型材料中的价带和导带的能量水平。
This is because, trivalent impurities exert lower
这是因为三价杂质所产生的影响（或作用）较弱（/较小）……
forces on the outer-shell electrons and lower forces mean that the electron orbits are slightly larger and have greater energy.
外层电子所受的力较小，因此电子的轨道稍微较大，能量也相应较高。
If we try to examine the energy
如果我们试图研究这种能量……
diagram for a pn junction at the
PN结的示意图
instant of formation, we can see that
在组织成立的那一刻，我们就可以看出……
the valence and conduction bands in the n region are at a noticeably lower energy level compared to the p region valence and conduction bands.
N区域的价带和导带所处的能量水平明显低于P区域的价带和导带。
But, we can also see that the
但是，我们也可以看到……
upper part of the conduction band in the n region and the lower part of the conduction band in the p region overlap.
N区导带的上部与P区导带的下部发生了重叠。