Strain profile, electronic band structure and optical gain of self-assembled Ge quantum dots on SiGe virtual substrate (original) (raw)

Group IV (Si, Ge, Sn) alloys are promising materials for future optoelectronic devices. Their compatibility with Si technology would allow us to engineer novel growth techniques and bandgap engineering methods to obtain direct band gap materials. Other alloy compositions could allow wider wavelength range which can revolutionize the photonics industry - leading to new design of LEDs, photodetectors, laser diodes and electro optical modulators. In this paper, we study one such possible structure - self assembled Ge QDs embedded on Si0.5Ge0.5 virtual substrate with the same capping layer. A wetting layer is considered to simulate the actual scenario. Then we conduct a theoretical study on the strain and electronic band structure of this model. We employ the valence force field (VFF) method using Keating potential to estimate the strain followed by 8 band k∙p method to calculate the electronic band structure taking the 𝛤 valley into consideration. Finally we study the optical gain of the system for varying carrier concentrations.