The p-type semiconductor and n-type semiconductor are fabricated on the same semiconductor (usually Si or GE) substrate by different doping processes and diffusion. The space charge region is called PN junction at their interface. The PN junction has single conductivity. P is the abbreviation of positive, and N is the abbreviation of negative, which indicates the characteristics of the interaction between positive and negative chargers.
In a single crystal semiconductor, the transition region near the interface between p-type solar cell and n-type solar cell is called PN junction when one part of the semiconductor doped with acceptor impurity is p-type semiconductor and the other part doped with donor impurity is n-type semiconductor. There are two kinds of PN junction: homojunction and heterojunction. The PN junction solar cell made of the same semiconductor material is called homojunction, and the junction solar cell made of two semiconductor materials with different bandgap is called heterojunction. The methods of manufacturing PN junction include alloy method, diffusion method, ion implantation method and epitaxial growth method. Heterojunction is usually fabricated by epitaxial growth.
The capacitance effect of PN junction solar cell is determined by two factors. One is barrier capacitance CB, the other is diffusion capacitance CD，N-type semiconductor (n means negative): it is composed of monocrystalline silicon doped with a small amount of pentavalent elements through a special process, which will form negative free electrons in the semiconductor.The interaction between n-junctions can produce amplification, oscillation and other electronic functions. PN junction solar cell is the core of bipolar transistor and field effect transistor, and is the basis of modern electronic technology. It is widely used in secondary pipe.
There are n-type and p-type gallium arsenide semiconductors, depending on what you doped. It can be judged by the Hall effect test. The thermal probe method and the like can also be used. The p-type is doped with beryllium and the n-type is doped with tellurium.