Strain-Induced Intrinsic Splitting of the Biexciton Ground State in SiGe/Si Quantum Wells

Abstract

We investigate the possibility of achieving the coherence of a biexciton gas in SiGe/Si heterostructures when the degeneracy of electronic states is reduced by anisotropic deformation. We find that at a temperature of 2K, the increase in the visible luminescence upon application of the deformation amounted to 3.3–3.9. The effect turned out to be much stronger than at 5K (the gain in 2.3) and can indicate either the splitting of the ground state of biexcitons in a strainless structure or the appearance of coherence in a dense biexciton 2D gas.