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 1.5 mum are reported in this paper. The Si/Ge quantum dots were made by commercial ultra-high vacuum chemical vapor deposition techniques at 600 degreesC. The photoluminescence spectrum shows a 1.55 mum emission peak at room temperature. Low and high temperature (710 degreesC) oxides are used as passivation layers for the mesa surface. The high temperature oxidized samples exhibit low device leakage currents and a 2 x 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 1.3 mum. The low temperature oxidation results in large device leakage current and lower emission intensity but leaves the emission peak at 1.5 mum. (C) 2003 Elsevier B.V. All rights reserved.