Explanation:
Semiconductors are materials that have conductivity between conductors and insulators. The resistivity of a semiconductor depends upon its atomic nature, which is explained below:

Band Structure:
The resistivity of a semiconductor depends on its band structure. Semiconductors have a band structure consisting of a valence band and a conduction band separated by a bandgap. The valence band is filled with electrons, and the conduction band is empty. To conduct electricity, electrons must jump from the valence band to the conduction band, which requires energy. The energy required is equal to the bandgap energy.

Intrinsic Concentration:
The resistivity of a semiconductor also depends on its intrinsic concentration. The intrinsic concentration is the concentration of electrons and holes at thermal equilibrium. At thermal equilibrium, the number of electrons in the conduction band is equal to the number of holes in the valence band. The intrinsic concentration is determined by the bandgap energy and temperature.

Doping:
Doping is the process of intentionally adding impurities to a semiconductor. This changes the conductivity of the semiconductor. Doping introduces energy levels within the bandgap, which allows electrons to move more easily between the valence and conduction bands. The resistivity of a doped semiconductor depends on the concentration and type of impurities added.

Temperature:
The resistivity of a semiconductor also depends on temperature. As temperature increases, the number of electrons in the conduction band increases, which reduces the resistivity. However, at high temperatures, the mobility of electrons decreases, which increases the resistivity.

Therefore, it can be concluded that the atomic nature of a semiconductor plays a crucial role in determining its resistivity.