What is a Semiconductor Device?
The semiconductor device is a type of electronic circuit that is neither a good conductor nor an excellent insulator. The advantages of these devices include their low cost, their reliability, and their compactness. It has become extremely popular in recent decades to use these devices in the manufacture of various electronics. Electricity can flow freely through most metals since they act as good conductors. Materials widely used in electronics include copper and aluminum. Similar to glass, wood, and plastic, electrical current is prevented by these insulating materials. The properties of semiconductors are a fusion of conductivity and insulation. Their electrical conductivity is lower at room temperature than that of conductors. Nevertheless, semiconductor devices are highly conductible at this point when compared to insulators.
Semiconductor Devices: Holes and Electrons
Electronic charge is carried by electrons and holes in semiconductors. Positively charged particles are carried by holes, while negatively charged particles are carried by electrons. Both holes and electrons have the same magnitude. Although they have different polarities, they possess the same magnitude.
Properties of Semiconductors
Under ideal conditions or circumstances, semiconductor devices are able to conduct electricity. However, there are a number of other attributes to consider.
An increase in temperature (applying heat) results in an increase in the conductivity of the semiconductor.
Electrons and holes flow along the semiconductor.
This results in reduced power loss.
Performing doping increases the efficiency of semiconductor devices.
As the temperature rises, resistance decreases.
Semiconductor Device Types
Three-terminal devices and two-terminal devices are the two broad categories of semiconductors. These two categories are distinguished in terms of their physics.
1. Two-terminal Semiconductors – It is a semiconductor material that only contains one positive-negative (p-n) junction.
2. Three-terminal Semiconductors – Positive-negative-positive (P-N-P) junctions are found in these semiconductor materials.
What are Diodes?
It consists of a single p-n junction and is a semiconductor device. In most cases, p-n junctions are formed when p-type and n-type semiconductor materials are combined. The electrons diffuse from the n-type region to the p-type region because the n-type region has more electron concentrations whereas the p-type region has more hole concentrations. As a result, light is generated by this phenomenon.
What are Transistors?
Bipolar junction transistors and field-effect transistors are two types of transistors. Bipolar junction transistors are created by forming two p-n junctions in different configurations, such as n-p-n or p-n-p. Three regions are formed in the transistor and are referred to as the emitter, collector, and base, or middle region.
An electric field can alter the conductivity of the field-effect transistor, which is based on the principle of conductivity.
Examples of Semiconductor Devices
Multiple Choice Questions
1. Which of These is an Example of Conductors?
Wood
Copper
Glass
Plastic
Ans. (b) Copper
FAQs on Semiconductor Devices
1. What are semiconductor devices, and how are they classified based on terminals?
Semiconductor devices are electronic components made from materials like silicon and germanium that exhibit conductivity between conductors and insulators. They are classified as two-terminal devices (such as diodes, which have a single p-n junction) and three-terminal devices (such as transistors, which have two p-n junctions and regions called emitter, base, and collector).
2. How do temperature changes affect the conductivity of semiconductors?
When the temperature increases, the electrical conductivity of a semiconductor rises. This is because more electrons gain enough energy to move to the conduction band, resulting in higher current flow. Thus, in semiconductors, conductivity is directly proportional to temperature.
3. What are the main differences between intrinsic and extrinsic semiconductors?
Intrinsic semiconductors are pure materials without impurities, while extrinsic semiconductors are doped with minute amounts of other elements to improve conductivity. Doping creates either n-type (more electrons) or p-type (more holes) semiconductors, enhancing their use in devices like diodes and transistors.
4. Why is doping important in the performance of semiconductor devices?
Doping is the process of adding controlled impurities to a semiconductor to modify its electrical properties. It increases carrier concentration—either electrons or holes—thereby improving conductivity and making the devices more efficient and reliable for various electronic applications.
5. Explain the working of a diode using the concept of p-n junction.
A diode consists of a p-n junction where p-type (hole-rich) and n-type (electron-rich) materials meet. When forward biased (positive voltage to p-side), current flows as electrons and holes move across the junction. In reverse bias, the junction blocks current flow, allowing the diode to act as a one-way switch.
6. How are semiconductor materials used in daily-life electronic devices?
Semiconductor materials are integral to many devices such as
- Microprocessors and logic circuits (in computers, smartphones)
- LEDs and display screens
- Power rectifiers and voltage regulators
- Washing machines, refrigerators, and digital cameras
7. What role do transistors play in electronic circuits?
Transistors function as amplifiers and switches in electronic circuits. They control the flow of current using a small input signal to regulate a larger output current, making them fundamental in building logic gates, microprocessors, and analog amplifiers.
8. Why are semiconductors neither perfect conductors nor perfect insulators? What advantage does this offer?
Semiconductors have a moderate energy gap between the valence and conduction bands, unlike conductors (no gap) or insulators (large gap). This unique property allows them to control current precisely, making them ideal for forming devices that can switch or amplify signals in electronics.
9. What would happen if only intrinsic semiconductors were used in electronic devices?
If only intrinsic semiconductors were used, devices would have low conductivity, resulting in poor efficiency and limited functionality. Doping is essential to enhance their properties and make them viable for practical electronic applications.
10. How do semiconductor devices contribute to energy efficiency in electronic appliances?
Semiconductor devices operate with low power loss and high reliability. Their ability to control current flow precisely allows for reduced energy consumption and improved performance in electronic appliances, supporting sustainable and compact gadget designs.
