Laser and transistor material on Si substrate

In this work we study Ge structures grown on silicon substrates. We use photoluminescence and photoreflectance to determine both direct and indirect gap of Ge under tensile strain. The strain is induced by growing the Ge on an InGaAs buffer layer with variable In content. The band energy levels are modeled by a 30 band k·p model based on first principles calculations. Characterization techniques show very good agreement with the calculated energy values.