Semiconductors do posses unique properties that the other materials (insulators and conductors) do not exhibit. These properties occur due to the fact that the electrons can move to and fro between the valence and conduction bands. Temperature is the driving force vital in rendering a semiconductor its conductivity. As such, it enables a vacuum to be created behind as an electron shifts to the conduction band. Moreover, apart from temperature, light can also achieve this electron -hole phenomenon which is also known as absorption. Conductivity in semiconductors increases in presence of light in a process referred to as photoconductivity.1Â Ideally, light is dual in nature; it behaves like a particle and a wave at the same time.1Â As a particle, light is emitted as small packets called photons.
Whatever happens when light is shone on a semiconductor is that photons having the right energy are absorbed by the material.4Â Consequently, those electrons that have received optimum energy from the photons vacate the valence band heading towards the conduction band. The degree of conductivity is dependent on the electron flux in the conduction band.
