emitter region

The lateral PNP has its collector and emitter regions side by side with a wide base region in between.

This is made possible because the emitter region is heavily doped, so providing far more free electrons than is necessary for the very small base-emitter current.

A BJT consists of three differently doped semiconductor regions: the emitter region, the base region and the collector region.

Typically, the emitter region is heavily doped compared to the other two layers, whereas the majority charge carrier concentrations in base and collector layers are about the same.

This limits the injection of holes from the base into the emitter region, since the potential barrier in the valence band is higher than in the conduction band.

In a non-uniformly and heavily doped emitter region of a bipolar transistor, the continuity equation and the minority-current equation cannot be solved exactly in closed form.

The transistor laser is a heterojunction bipolar transistor (using different materials between the base and emitter regions) that employs a quantum well in its base region that causes emissions of infrared light.

The collector surrounds the emitter region, making it almost impossible for the electrons injected into the base region to escape without being collected, thus making the resulting value of α very close to unity, and so, giving the transistor a large β.

The heavy doping of the emitter region and light doping of the base region causes many more electrons to be injected from the emitter into the base than holes to be injected from the base into the emitter.

In an MCS the positive difference between the voltage of regulation element and conduction voltage drop of MOSFET is applied to location between the collector region and emitter region of the pnp transistor.