Room temperature 1.3 and 1.5 μm electroluminescence from Si/Ge quantum dots (QDs)/Si multi-layers

Electroluminescence devices that use Si/Ge multilayer quantum dots as emission material emitting at 1.3 and 1.5μm are reported in this paper. The Si/Ge quantum dots were made by commercial ultra-high vacuum chemical vapor deposition techniques at 600°C. The photoluminescence spectrum shows a 1.55μm emission peak at room temperature. Low and high temperature (710°C) oxides are used as passivation layers for the mesa surface. The high temperature oxidized samples exhibit low device leakage currents and a 2×10 ^-7 external quantum efficiency at room temperature. However, the high temperature process causes Si and Ge to inter-diffuse and makes the emission shift to 1.3μm. The low temperature oxidation results in large device leakage current and lower emission intensity but leaves the emission peak at 1.5μm.