Q1. A defect in Si (Eg = 1.12 eV) introduces two levels in the gap: a donor level at Ev + 0.25 eV and an acceptor level at Ev + 0.75 eV. Illustrate graphically.
Q2. Explain the influence of magnetic anisotropy on the behavior of magnetic nano-particles.
Q3. Explain the basic principle of a spin-valve device: discuss the relation between the magneto resistance and the magnetization of the materials changes with magnetic field.
Q4. Explain the physical principles of tunneling magneto resistance and discuss the relevance of materials (electrodes and barrier) involved.
Q5. Consider an ideal Schottky barrier. The semiconductor is n-type (p-type) and no degenerate. Draw respective energy band schemes:
a) For the barrier in equilibrium;
b) For the barrier with a direct bias U applied (|U|<|Ubi|);
c) For the barrier with a reverse bias U applied.