Electroluminescence from metal/oxide/strained-Si tunneling diodes

The metal-oxide-silicon light-emitting diode under biaxial tensile mechanical strain is studied. The emission line shape of the device can be fitted by the electron-hole-plasma recombination model. The energy gap of strained Si extracted by the light emission spectra at the temperature of 120 K is reduced by 15 meV under 0.13% biaxial tensile strain. The light intensity of the device under 0.13% biaxial tensile strain increases 9% as compared to the relaxed-Si device. The upshift of valence band edge under mechanical strain to increase the majority hole concentration at the oxide/Si interface may be responsible for this light emission enhancement. The mechanical strain is measured by Raman spectroscopy, strain gauge, and analyzed by the finite element method. (c) 2005 American Institute of Physics.