SEMICONDUCTORS
Introduction
Semiconductors are materials that have unique electrical properties, making them the foundation of modern electronics. The invention of the transistor, which is based on semiconductor technology, revolutionized the field of electronics and ushered in the digital age. Semiconductors are used in a wide range of electronic devices, including computers, smartphones, and televisions. In this blog, we will explore the history and properties of semiconductors and their applications in modern electronics.
What are Semiconductors?
A semiconductor is a material that has an electrical conductivity that falls between that of an insulator and a conductor. In other words, a semiconductor has a conductivity that is higher than an insulator but lower than a conductor. The most common semiconductor material is silicon, which is used in the production of microchips and transistors.
The electrical properties of semiconductors are due to the unique arrangement of electrons in their atomic structure. The electrons in a semiconductor are arranged in energy bands. There are two types of energy bands in a semiconductor, the valence band and the conduction band. The valence band contains the electrons that are bound to the atoms in the semiconductor. The conduction band contains the electrons that are free to move in the semiconductor.
In a semiconductor, the energy gap between the valence band and the conduction band is relatively small. This means that the electrons in the valence band can be easily excited to move to the conduction band, where they are free to move and carry an electrical current. This property is what makes semiconductors useful for electronic applications.
History of Semiconductors
The history of semiconductors can be traced back to the discovery of the photoelectric effect by Albert Einstein in 1905. The photoelectric effect is the phenomenon in which electrons are emitted from a metal surface when it is exposed to light. This discovery led to the development of the first solid-state device, the diode, by John Ambrose Fleming in 1904.
The first semiconductor device, the crystal detector, was developed in 1906 by Henry Joseph Round. The crystal detector was a type of diode that used a semiconductor crystal instead of a metal surface. The crystal detector was used in the first radio receivers, but it was not very efficient.
In the 1930s, the development of the point-contact transistor by John Bardeen and Walter Brattain marked a major breakthrough in semiconductor technology. The point-contact transistor was the first solid-state amplifier and was used in early computers and radios.
The invention of the junction transistor by William Shockley, John Bardeen, and Walter Brattain in 1947 was another milestone in semiconductor technology. The junction transistor was more efficient than the point-contact transistor and revolutionized the field of electronics.
The development of the integrated circuit by Jack Kilby and Robert Noyce in the 1960s marked another major milestone in semiconductor technology. The integrated circuit was a complete electronic circuit that was fabricated on a single chip of semiconductor material. This invention paved the way for the development of modern electronics, including computers, smartphones, and televisions.
Properties of Semiconductors
The unique electrical properties of semiconductors make them useful for electronic applications. Some of the important properties of semiconductors are:
Band Gap: The energy gap between the valence band and the conduction band is an important property of semiconductors. The band gap determines the electrical conductivity of the material. Semiconductors with a small band gap are more conductive than semiconductors with a large band gap.
Doping: Doping is the process of introducing impurities into a semiconductor material to change its electrical properties.
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