4. Explain (using conduction band, valance band and forbidden gap band) why a s mall increase in temperature/e nergy will lead to conduction of semiconductors. (3 mks)

In semiconductors, the valence band is the energy band where electrons are located at absolute zero temperature. The conduction band is the energy band where electrons can move freely. The forbidden gap, also known as the band gap, is the energy difference between the valence band and the conduction band.<br /><br />When a small increase in temperature or energy is applied to a semiconductor, it provides enough energy to some of the electrons in the valence band to jump into the conduction band. This process is called thermal excitation. As the temperature or energy increases, more electrons gain enough energy to jump into the conduction band, resulting in an increase in the number of free electrons available for conduction.<br /><br />The conduction band, valence band, and forbidden gap band are crucial in understanding the behavior of semiconductors. The small increase in temperature or energy leads to thermal excitation, which causes electrons to jump from the valence band to the conduction band. This results in an increase in the number of free electrons available for conduction, which is why a small increase in temperature or energy can lead to conduction in semiconductors.