1. How many intrinsic electrons and holes are there in a thermal de Broglie cube at 300K in Si corresponding to an energy equal to kBT? What is the thermal fluctuation in carrier density In this cube? Can the intrinsic electrons be localized?
2. The binding energy of an electron trapped to the substitutional As donor in Si was measured spectroscopically (infra-red absorption at T=4.2K) in 1965 by Prof. Ramdas and his graduate students at Purdue and found to be 53.69meV.
Assume that the static dielectric constant is valid for screening the As ion charge by the valence electrons and is given by ε1/ ε0 = 01.8. What is the orbital radius of an electron trapped at the ground state by As?
How many valence electrons are enclosed in the Bohr sphere or in the spherical volume enclosed by the trapped electron orbit? Is the assumption on the static dielectric constant reasonable and why?