|
Y.-H. Kuo,
Y. K. Lee, Y. Ge, S. Ren, J. E. Roth, T. I. Kamins, D. A. B. Miller, and
J. S. Harris Jr., "Quantum-Confined
Stark Effect in Ge/SiGe Quantum Wells on Si for Optical Modulators
," IEEE J. Sel. Top. Quantum Electron. 12, 1503-1513 (2006)
We present observations of
quantum confinement and quantum-confined Stark effect (QCSE)
electroabsorption in Ge quantum wells with SiGe barriers grown on Si
substrates, in good agreement with theoretical calculations. Though Ge
is an indirect gap semiconductor, the resulting effects are at least as
clear and strong as seen in typical III-V quantum well structures at
similar wavelengths. We also demonstrate that the effect can be seen
over the C-band around 1.55-µm wavelength in structures heated to 90°C,
similar to the operating temperature of silicon electronic chips. The
physics of the effects are discussed, including the effects of strain,
electron and hole confinement, and exciton binding, and the reasons why
the effects should be observable at all in such an indirect gap
material. This effect is very promising for practical high-speed,
low-power optical modulators fabricated compatible with mainstream
silicon electronic integrated circuits.
Full text available for
download
|