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.

In this study, we introduce a thin nickel interlayer to enhance the phase separation and silicon nanocrystal (Si-NC) growth in Si-rich silica films. Through TEM analysis, it is observed that the Si-NC density in the sample with a Ni interlayer is 2.6 times higher than that of the sample without Ni after high temperature annealing. The photoluminescence (PL) spectrum of the sample with a Ni interlayer is 2-5 times stronger than the one without Ni according to different silicon excess. By analysing the samples after rapid thermal annealing (RTA) with Fourier transform infrared absorption (FTIR), we find that nickel can induce phase separation in Si-rich silica films during annealing. Thermodynamic and kinetic analysis indicates a reduction of 31.4 kJ mol −1 in the Si-NC nucleation activation free energy by adding the nickel interlayer, which subsequently results in higher Si-NC density.

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