What defines a degenerate semiconductor?

A degenerate semiconductor is characterized by its heavy doping level, which has a significant impact on the electronic properties of the material. In a degenerate semiconductor, the doping is so intense that the Fermi level moves into the conduction band for n-type materials or into the valence band for p-type materials. This causes the semiconductor to behave more like a metal than a typical semiconductor.

Heavy doping introduces a large concentration of charge carriers, which affects how the material conducts electricity. When the Fermi level moves outside the intrinsic band gap as a result of this high level of dopants, it signifies that there is not just a conduction band and a valence band; rather, the band structure has been altered due to this excessive doping. This unique situation is crucial, as it defines the behavior of the semiconductor under various conditions of electrical and thermal excitation.

Other options do not accurately reflect the characteristics of a degenerate semiconductor. For example, having a higher band gap is not a typical trait of degenerate semiconductors; instead, the heavy doping alters the distribution of carriers without necessarily changing the intrinsic band gap. Similarly, a degenerate semiconductor can conduct electricity quite well due to the high concentration of charge carriers, contrary to the option suggesting it cannot conduct electricity