1. For advanced students, determine mathematically (analytically) if there is a minimum limit on the depth and width of the square well in order to bind the second electron.
2. The experimental electron affinity to an isolated neutral Si atom is 1.39eV while the lionization potential is 8.151eV.
In analogy to Figure 1 and 2, illustrate the electron attachment and detachment transitions at the neutral and negatively charged Si atom by the two energy level diagrams and two transition energy diagrams or energy change diagrams.