I love your teaching style and I love that you devoted your time for chalking on blackboard. Now I understand clearly about the Schottky and nearly Ohmic. Thank you so much.
it is a very useful lecture. Professor, could you please advise in the case of junction between Au and In2O3? What metal is best for In2O3 so that I could get a very near Ohmic contact? Thank you very much.
Is the case where the work function of metal is lower than the electron affinity of the semiconductor like a 2DEG where electrons are trapped in potential well?
1. When you connect two different materials (metal and semiconductor in this case) without any external bias, charges flow from one material to another until the Fermi levels align. This corresponds to the “Equilibrium energy band diagram” 2. When you apply voltage across a device which has achieved equilibrium, you add energy to (or subtract energy from, depending on the polarity) every energy state in the bulk of one of the materials relative to the other material. Hence, for this reverse biased case which you asked about, every energy state (Ec, Ev, EF and Evacuum included) in the bulk of the semiconductor moves “downward” in energy relative to the metal. (Note however that the energy levels at the junction are pinned) Hence, the Fermi levels are not aligned any more. Long story short, Fermi levels align only under equilibrium (applies to semiconductor-semiconductor junctions also)
