4. It is known from measurements that the semiconductor bandgap changes under pressure (mechanical stress). For instance, the bandgap of silicon decreases linearly with pressure at the rate of 2x10-3 eV/kbar (1 kbar = 1.02x10 kg/cm ). Suppose we have a piece of extrinsic silicon with a donor concentration of 101/cm, Eo = 1.1 eV, Nc = 2.8x10"/cm' and Nv = 1x109/cm for silicon at room temperature. a. Calculate the electron concentration n hole concentration p, and the intrinsic concentration n; at both zero stress and at a stress of 10 kbar. b. Can extrinsic silicon be used as a pressure transducer (i.e., do the carrier concentrations change significantly)? Explain. c. Would intrinsic silicon be a better pressure transducer? Explain. 5. The E vs. k diagram of a semiconductor is shown levy conduction Band . Valence Band sk - Ila +Tla a. b. Estimate Eg for this semiconductor. Assuming the lattice constant is a = 4 , estimate the energy change and the momentum change that must take place when an electron goes from the valence band to the conduction band. 4. It is known from measurements that the semiconductor bandgap changes under pressure (mechanical stress). For instance, the bandgap of silicon decreases linearly with pressure at the rate of 2x10-3 eV/kbar (1 kbar = 1.02x10 kg/cm ). Suppose we have a piece of extrinsic silicon with a donor concentration of 101/cm, Eo = 1.1 eV, Nc = 2.8x10"/cm' and Nv = 1x109/cm for silicon at room temperature. a. Calculate the electron concentration n hole concentration p, and the intrinsic concentration n; at both zero stress and at a stress of 10 kbar. b. Can extrinsic silicon be used as a pressure transducer (i.e., do the carrier concentrations change significantly)? Explain. c. Would intrinsic silicon be a better pressure transducer? Explain. 5. The E vs. k diagram of a semiconductor is shown levy conduction Band . Valence Band sk - Ila +Tla a. b. Estimate Eg for this semiconductor. Assuming the lattice constant is a = 4 , estimate the energy change and the momentum change that must take place when an electron goes from the valence band to the conduction band