Adding silicon atoms (3+4=7), this compound will form an empty electron space, and scientists will

This life is called "hole", and this compound is a P-type semiconductor, which acts as a receptor. In other words, will

The element of IV A group added to silicon atom will give an extra electron because of 5＋4=9. This kind of compound

It is an N-type semiconductor and plays the role of a donor.

D‧PN junction (PN junction) diode is a combination of N-type semiconductor and P-type semiconductor. exist

The electrons and electric forces in the PN junction (PN junction) area will cancel each other out, resulting in a shortage of main carriers, forming

In the depletion zone, the N-type side is positively charged and the P-type side is negatively charged in the depletion zone, so an electrostatic field is generated inside.

There is a potential difference across the depletion layer. But if the carriers at both ends are recombined, the voltage difference between the two ends will beBecomes zero.

Connect a positive voltage to a P-type semiconductor, and a negative voltage to an N-type semiconductor. This type of P-type is connected to a positive voltage, and the N-type

The circuit connection with negative voltage is called forward bias. At this time, all energy levels at the negative voltage terminal will increase upwards.

As a result, the original equilibrium state is destroyed, and the energy barrier encountered when electrons flow to the left in the conductive band is also reduced,

Therefore, it is very easy to circulate, forming an "on" state in the circuit, and the current rises rapidly because of this.

Under a proper forward bias, after the electrons and holes are injected into the N and P terminals from the dry cell, they will be in the P

The N interface region combines to emit light, that is, the electrons fall back from the high-energy state to the low-energy state and combine with the holes,

Energy is released in the form of light.