Problem 4. (20 points) Temperature (K) 1,000 300 200 100 Intrinsic density (cm) 0 2 10 12 4 6 8 1000/T (1000/K) The figure shows carrier densities in three different intrinsic semiconductors. Assume the gap is 1.1 eV in the material B. Estimate the gap size for the materials A and C. Which one(s) can be used for photodetectors for the red light? Problem 4. (20 points) Temperature (K) 1,000 300 200 100 Intrinsic density (cm) 0 2 10 12 4 6 8 1000/T (1000/K) The figure shows carrier densities in three different intrinsic semiconductors. Assume the gap is 1.1 eV in the material B. Estimate the gap size for the materials A and C. Which one(s) can be used for photodetectors for the red light