Semiconductor

what is a Semiconductor?

A material whose electrical conductivity lies between that of a conductor and an insulator

. Semiconductors have a small energy gap between the valence and conduction bands.

Intrinsic Semiconductor

A pure semiconductor without any significant impurity atoms, where the number of free electrons is equal to the number of holes.

Extrinsic Semiconductor

A semiconductor that has been doped with impurity atoms to increase its conductivity, such as n-type and p-type.

Doping

The process of adding impurity atoms to a pure semiconductor to improve its conductivity.

n-Type Semiconductor

A semiconductor doped with pentavalent impurities, which results in more free electrons.

p-Type Semiconductor

A semiconductor doped with trivalent impurities, which results in more holes.

Diode

A semiconductor device that allows current to flow in only one direction, formed by joining a p-type and n-type semiconductor.

p-n Junction

The boundary between a p-type and n-type semiconductor, forming a junction.

Forward Bias

When the positive terminal of the battery is connected to the p-type semiconductor, allowing current to flow.

Reverse Bias

When the positive terminal of the battery is connected to the n-type, preventing current flow.

Junction Diode as a Rectifier

A diode used to convert alternating current (AC) into direct current (DC) through half-wave and full-wave rectification.

Zener Diode

A special diode designed to operate in the reverse breakdown region, used for voltage regulation.

Light Emitting Diode (LED)

A diode that emits light when current flows in forward bias; the light emitted depends on the band gap of the semiconductor.

Photodiode

A diode that generates current when exposed to light, used in light-detection applications.

Transistor (Bipolar Junction Transistor - BJT)

A semiconductor device used to amplify or switch electronic signals, consisting of three regions: emitter, base, and collector.

Logic Gates

Electronic circuits used in digital systems to perform logic operations like AND, OR, and NOT.

Integrated Circuit (IC)

A microelectronic device that integrates several electronic components on a small chip.

explain working of forward biasing

1) in forward biasing p side of diode is connected to the positivs terminal of the battery and n side is connected to negative terminal

2) due to replusion of chargres a potential barrier is generated

3) if the external voltage provided by the battery is greater than the value of potential barrier (>0.7v) the oppostion of potential barrier will be overcome and current will flow through the diode.

4) this is because the electrones are pushed forward by the battery, allowing them to recombine with holes in the p-type material, resulting in a flow of charge.

50 depletion region is deacreased

6) resistance of the diode decreases,

explain working of reverse biasing

1. In reverse biasing, the p side of the diode is connected to the negative terminal of the battery and the n side is connected to the positive terminal

2. therefore the charges are atrracted towards the battery

3. This widens the depletion region and increases the potential barrier, preventing current flow.

4. Only a small leakage current flows until the breakdown voltage is reached.

5. but after breakdown voltage is increase the diode conducts current in the reverse direction, potentially damaging the diode if the current is excessive.

working of zener diode

1. highly doped

2. breakdown voltage upto 23V

3. used in reversed bais

4. used to conver fluctuating current into complete DC

5. used as voltage regulator