The principle of PN junction formation

Sophomore study of the mode of electricity, and now picked up, lamented that their learning is too poor, so start summarizing notes with some information

PN Junction i.e. space charge zone

Many sub-particles in impurity semiconductors are generally provided by the impurity atoms, and the small children are the intrinsic excitation generation

After the combination of P-type semiconductor and N-type semiconductor, the multi-sub (hole) of the junction p region spreads to n region, and N-Region multi-sub (electrons) spreads to P-zone.

The former is because the hole in N region produces less concentration difference, the latter is because the electron in P region produces less concentration difference, which produces the diffusion

Here the hole movement is relative, p region of the hole by the N region over the electron union, so the P area is less a hole, and N-zone electron left after leaving a hole, it is like the hole from the P-zone diffusion to the N zone, is actually relatively.

After diffusion, there is a compound, that is, the electrons in the N region are combined with the diffusion of the hole, and the hole in P region is combined with the diffusion of electrons.

This results in n-zone impurity atoms lose electrons, leaving a positively charged impurity ions, the P-zone loses the hole, that is, to get electrons, leaving negatively charged impurity ions (against the following reasons)

Thus the so-called space charge is the depletion zone, i.e. PN Junction

The P-Zone is an anion region, N-Zone positive ion region, these ions can not be moved (the ions in the solution may move, not in the solids), thus forming an electric field

(Cause: Atoms are made up of nuclei and electrons, the nucleus is positively charged, and electrons orbiting the nucleus have opposite negative charges.) The atomic nuclear charge is equal to the number of electrons outside the nucleus, so the atom is electrically neutral.

When atoms get one or several electrons, the number of electrons outside the nucleus is more than the number of nuclear charges, thus negatively charged, called anions. When an atom loses one or several electrons, the number of electrons outside the nucleus is less than the number of nuclear charge, and thus positively charged, called a cation. ）

P and N-type semiconductors are electrically neutral, the difference is that their carrier polarity is different, so the P or N-type semiconductor is wrong to display electricity

The principle of PN junction formation