ROOM-TEMPERATURE ELECTROLUMINESCENCE FROM SI GE/SI1-XGEX QUANTUM-WELLDIODES GROWN BY MOLECULAR-BEAM EPITAXY/

Tunable room-temperature electroluminescence, photocurrent, and photol uminescence in the near infrared (lambda-1.3 mu m) has been observed f rom Ge/Si/Ge/Si1-xGex quantum-well (QW) diodes grown by molecular-beam epitaxy. The QWs are grown on a p(+)-doped (100)-Si substrate and con sist of two thin Ge wells separated by a thicker Si middle layer, and the whole structure is embedded by two S0.85Ge0.15 ahoy layers. Our th eoretical analysis of the data suggests that the strength of the spect ra is linked to states localized at the interface. (C) 1996 American I nstitute of Physics.