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We report the first observation of photoluminescence from electron-hole plasmas in Si/S&,sGe&Si quantum wells. While at liquid helium temperature, luminescence due to shallow bound excitons is observed. At 77 K electron-hole plasma (EHP) luminescence dominates the spectra over a wide range of pump powers. Convolution of the occupied electron and hole densities of states gives an excellent fit to the photoluminescence line shape. A bandgap reduction of up to 15 meV at high carrier densities is observed for wide quantum wells, but no such shift is detected for narrow quantum wells.
We report the first room-temperature 1.3 ,um electroluminescence from strained Sir-,Ge,/Si quantum wells. The electroluminescence is due to band-edge carrier recombination, and its intensity increases linearly with the forward current up to 1700 A/cm'. The internal quantum efficiency is estimated to have a lower limit of 2 x 10m4. As the temperature is increased from 77 to 300 K, luminescence from the silicon increases relative to that from the Sit-,GeX wells. A minimum band offset is required to have effective room-temperature luminescence from the Sr,-XGeX quantum wells.
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