As a semiconductor materials expert with a background in electrical engineering, I can provide a detailed explanation of how temperature affects the resistance of semiconductors.

Semiconductors are materials that have electrical conductivity between that of a conductor and an insulator. Their unique properties make them crucial for a wide range of electronic devices, including transistors, diodes, and solar cells. The resistance of a semiconductor is influenced by several factors, with temperature being one of the most significant.

The relationship between temperature and resistance in semiconductors is governed by the behavior of charge carriers—electrons and holes. In semiconductors, electrons can move from the valence band, where they are bound to atoms, to the conduction band, where they are free to move and conduct electricity. This movement is temperature-dependent.

At lower temperatures, the energy levels of the valence electrons are not sufficient to overcome the energy gap between the valence and conduction bands. As a result, there are fewer free electrons available to conduct electricity, leading to higher resistance.

As the temperature increases, the kinetic energy of the valence electrons also increases. This added energy allows more electrons to gain enough energy to jump the energy gap and enter the conduction band. The increase in the number of free electrons in the conduction band enhances the electrical conductivity of the material, thus reducing its resistance.

However, this is not the only effect of temperature on semiconductor resistance. The creation of electron-hole pairs also plays a crucial role. When a semiconductor is heated, it can generate electron-hole pairs through a process called thermal generation. These holes in the valence band can move like positive charges, contributing to the conductivity of the material. The generation of electron-hole pairs increases with temperature, which also contributes to the decrease in resistance.

It's important to note that the relationship between temperature and resistance in semiconductors is not linear. The resistance decreases with increasing temperature, but the rate of decrease is not constant. It follows a characteristic curve that can be described by the semiconductor's material properties and the temperature coefficient of resistance.

Additionally, different types of semiconductors—such as silicon, germanium, and gallium arsenide—exhibit different temperature dependencies due to their unique band structures and energy gaps. For instance, silicon has a wider band gap than germanium, which means it requires more energy to excite electrons from the valence to the conduction band. This results in a different temperature response for silicon compared to germanium.

In summary, the resistance of a semiconductor decreases with increasing temperature due to the increased availability of free electrons in the conduction band and the generation of electron-hole pairs. The exact relationship is complex and depends on the material properties of the semiconductor and the specific temperature range being considered.

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As the temperature of the semi-conductor is increased, the electrons in the valence band gain sufficient energy to escape from the confines of their atoms. As a result, in higher temperatures, a semi-conductor's valence electrons are free = conduction results, resistivity decreases.read more >>