17 results about "Band bending" patented technology

Band bending refers to the local changes in the energy offset of a semiconductor's band structure near a junction, due to space charge effects. Because the common way to visualize the electron energy states and Fermi level in a material is to draw bands on an energy vs. distance plot, band bending refers to bending observed in these diagrams and does not correspond to any physical bending. The primary principle underlying band bending inside a semiconductor is space charge: a local imbalance in charge neutrality. Poisson's equation gives a curvature to the bands wherever there is an imbalance in charge neutrality. Why is there charge imbalance? Although one expects a homogeneous material to be charge neutral everywhere there is no such requirement for interfaces. Practically all types of interface develop a charge imbalance, though for different reasons: At the junction of two different types of the same semiconductor the bands vary continuously since the dopants are sparsely distributed and only perturb the system. At the junction of two different semiconductors there is a sharp shift in band energies from one material to the other; the band alignment at the junction is fixed.