Energy Levels of Valence Subbands in Si/Si_l-xGe_x Quantum Well by Admittance Spectroscopy

Using the admittance spectroscopy technique, energy levels of subbands in SiGe/Si quantum well are studied. The value of activation energy increases with increasing well width, in accordance with the quantum confinement effect. Two conductance peaks due to hole emission from heavy hole ground state and light hole ground state were observed. It was found that the value of activation energy increased with annealing time at the temperature of 800^oC, while the activation energy decreases with the annealing time at 900^oC.