Semiconductor Devices

Semiconductor Devices

Semiconductor Devices – A semiconductor material is a device that allows the passage of electric current through it. Consider the device CPU, it consists of many numbers of transistors within it and these transistors contain the semiconductor material which allows the passage of current and all these are controlled by a switch. Here in a transistor, the passage of electric current is controlled by the actions based on the state of the switch whether it is on or off. Hence such a device which allows the current to pass through them partially is called as Semiconductor Device.

Examples of Semiconductor Devices

These devices are said to be neither good insulators nor good conductors, hence the name ‘Semi Conductors’. Some of the examples of semiconductor devices include:

  • op-amps
  • resistors
  • capacitors
  • diodes
  • transistors

These devices are widely used in many of the applications due to their reliability, compactness, low cost. As a discrete component, a semiconductor is used as optical sensors, power devices, light emitters, and also including the solid-state lasers. They also have a large range of current as well as voltage handling capacities, with the current ratings ranging from few nano-amperes i.e (10−9 ampere) up-to more than about 5,000 voltage and ampere ratings which extend above 100,000 volts.

Semiconductor devices supply themselves in integrating into complex and readily are manufacturable into microelectronic circuits. They also find a good scope in the future in forming key components for the majority of electrical and electronic instruments and systems in various fields such as communications, data-processing, consumer, and also in industrial-control equipments.

Types of Semiconductor Devices

These devices are classified accordingly whether they are two-terminal or three- terminal devices and sometimes for terminal devices. The examples of two-terminal devices include Diode, Zener diode, Laser diode, Schottky diode, Light-emitting diode (LED), Photocell, Phototransistor, Solar cell and etc.

Some of the examples of three terminal semiconductor devices include Bipolar transistor, IGBT, Field-effect transistor, Silicon-controlled rectifier, TRIAC, Thyristor, etc.


A diode is a semiconductor device that comprises of single p-n junction. P-n junctions are usually formed by joining up of p-type and n-type semiconductor materials. This formation is due to the reason that n-type region has the higher number of electron concentration whereas the p-type region has a higher number of hole concentration, hence the electrons get diffused from the n-type region to the p-type region. Hence this phenomenon is used in generating light.


Transistors are of two types bipolar junction transistor and field effect transistor. The bipolar junction transistor is achieved by the formation of two p-n junctions in two different configurations like n-p-n or p-n-p. In this type of transistor, the three regions formed are named as emitter, collector, and base or the middle region.

The field effect transistor works on the principle of conductivity and the conductivity can be altered by the presence of an electric field.

Applications of Semiconductor Devices

  • They are used in the designing of logic gates and digital circuits.
  • These are used in microprocessors
  • They are used in analog circuits such as oscillators and amplifiers.
  • Used in high voltage applications.

Practise This Question

The following figure shows the elliptical path of a planet about the sun. The two shaded parts have equal areas. If t1, t2 be the time taken by the planet to go from A to B and from C to D respectively–