Band Gap Calculation for Semiconductor based on Electromagnetic Radiation

What happens to the electrical conductivity of a semiconductor when it is exposed to electromagnetic radiation with a wavelength shorter than 2480 nm?

A. Increases

B. Decreases

C. Remains the same

D. Not enough information to determine

Answer:

The electrical conductivity of a semiconductor increases when exposed to electromagnetic radiation with a wavelength shorter than 2480 nm.

When a semiconductor is exposed to electromagnetic radiation with a wavelength shorter than 2480 nm, the photons with sufficient energy can excite electrons from the valence band to the conduction band. This process effectively reduces the band gap of the semiconductor, leading to an increase in its electrical conductivity.

The band gap of the semiconductor can be calculated using the equation E = hc/λ, where E is the energy, h is Planck's constant, c is the speed of light, and λ is the wavelength of the incident light. By calculating the energy for the given wavelength and converting it to electron volts, the band gap for the semiconductor can be determined to be 0.5 eV.