Dope:
In semiconductor production, doping is the intentional introduction of impurities into an intrinsic semiconductor for the purpose of modulating its electrical, optical and structural properties. The doped material is referred to as an extrinsic semiconductor.
A semiconductor doped to such high levels that it acts more like a conductor than a semiconductor is referred to as a degenerate semiconductor.
In the context of phosphors and scintillators, doping is better known as activation. Doping is also used to control the color in some pigments
The different methods of doping semiconductors are given below:
i) The impurity atoms are added to the semiconductor in its molten state.
ii) The pure semiconductor is bombarded by ions of impurity atoms.
iii) When in the semiconductor crystal container the impurity atoms are heated, the impurity atoms diffuse into the hot crystal.
Introduction to Transistor:
Earlier, the critical and important component of an electronic device was a vacuum tube; it is an electron tube used to control electric current. The vacuum tubes worked but they are bulky, require higher operating voltages, high power consumption, yield lower efficiency, and cathode electron-emitting materials are used up in operation. So, that ended up as heat which shortened the life of the tube itself. To overcome these problems, John Bardeen, Walter Brattain, and William Shockley were invented a transistor at Bell Labs in the year of 1947. This new device was a much more elegant solution to overcome many of the fundamental limitations of vacuum tubes.
The transistor is a semiconductor device that can both conduct and insulate.
A transistor can act as a switch and an amplifier. It converts audio waves into electronic waves and resistors, controlling electronic current. Transistors have a very long life, smaller in size, can operate on lower voltage supplies for greater safety, and required no filament current. The first transistor was fabricated with germanium.
A transistor performs the same function as a vacuum tube triode but using semiconductor junctions instead of heated electrodes in a vacuum chamber. It is the fundamental building block of modern electronic devices and found everywhere in modern electronic systems.
