In physics lab, Ashwin was given with 3 semiconductors A, B and C having band gaps of 3eV,2eV and 1eV for use in photo detector to detect, λ = 1400 nm. Ashwin noticed that photo detector was not working with these semiconductors and did not know why. Ashwin friend Akash found the Ans. (a) Because threshold frequency was not provided.2 reason for it and explained it to him.
(a) Why did the photo detector not work ?
(b) What according to you are the values shown by Akash ?