Semiconductor is a class of solid whose conductivity increases with an increase in

Semiconductors are a type of solid material that can conduct electricity, but not as well as metals. Their ability to conduct electricity increases as more electrons are freed up to move around the material. This can happen in a few different ways, but the most common is by adding energy to the material. When we add energy to a semiconductor, for example by shining light on it or heating it up, some of the electrons in the material gain enough energy to break free from their atoms and move around. These free electrons can then carry an electric current through the material. As we add more energy to the material, more electrons are freed up, and the conductivity increases. So, the answer to the question is: Temperature. As the temperature of a semiconductor increases, more electrons gain enough energy to break free and conduct electricity, which increases the conductivity of the material.