Visible light does not enhance the conductivity of metals due to their partially filled conduction bands, which contain a high density of electrons. In contrast, photoconductivity is primarily observed in semiconductors, where visible light can excite electrons from the valence band to the conduction band, significantly increasing conductivity. This phenomenon occurs because semiconductors have a nearly full valence band and an empty conduction band, allowing for the generation of conduction electrons through photon interaction. The discussion emphasizes the fundamental differences in electron behavior between metals and semiconductors under visible light exposure.
PREREQUISITESStudents, researchers, and professionals in materials science, electrical engineering, and physics who are interested in the effects of light on electrical conductivity and the distinctions between metals and semiconductors.
Henryk said:No. Metal are substances which have partially filled conduction bands with electrons and the number of electrons is very high, one or two per atom.
Photoconductivity is observed mostly in semiconductors. Semiconductors have empty conduction band and almost full valence band just around 1 eV below.
The electrons in the conduction band are coming from either doping or are thermally excited and their number is rather small, one per millions of atoms.
When you shine light on a semiconductor you excite electrons from the valence to conduction band and the conductivity increases.