Direct and indirect band gap room temperature electroluminescence of Ge diodes

Germanium is a promising material for electrically pumped light emitters integrated on silicon. In this work, we have investigated the room temperature electroluminescence of pure germanium diodes grown by metal organic chemical vapor deposition. The dependence of the optical response of the p-n diodes is studied as a function of the injected current. Both direct and indirect band gap recombinations are observed at room temperature around 1.6 and 1.8 mu m. The amplitude of the direct band gap recombination is equivalent to the one of the indirect band gap. (C) 2010 American Institute of Physics. [doi:10.1063/1.3462400]