Temperature-dependent photoluminescence characteristics of GeSn epitaxial layers

Abstract

GeSn epitaxial heterostructures are emerging as prominent candidates for the monolithic integration of light sources on Si substrates. Here we propose a judicious explanation for their temperature-dependent photoluminescence (PL) that is based upon the so far disregarded optical activity of dislocations. By working at the onset of plastic relaxation, which occurs whenever the epilayer releases the strain accumulated during growth on the lattice mismatched substrate, we demonstrate that dislocation nucleation can be explicitly seen in the PL data. Notably, our findings point out that a monotonous thermal PL quenching can be observed in coherent films, in spite of the indirect nature of the GeSn bandgap. Our investigation, therefore, contributes to a deeper understanding of the recombination dynamics in this intriguing group IV alloy and offers insights into crucial phenomena shaping the light emission efficiency.

References in corpus (7)

• Photonic quantum technologies
• Silica-on-Silicon Waveguide Quantum Circuits
• Efficient room-temperature light-emitters based on partly amorphised Ge quantum dots in crystalline Si
• Testing foundations of quantum mechanics with photons
• Spin and energy relaxation in germanium studied by spin-polarized direct-gap photoluminescence
• Disentangling nonradiative recombination processes in Ge micro-crystals on Si substrates
• Spin-dependent direct gap emission in tensile-strained Ge films on Si substrates

Cited by in corpus (6)

• Ultra-low threshold cw and pulsed lasing in tensile strained GeSn alloys
• Reduced lasing thresholds in GeSn microdisk cavities with defect management of the optically active region
• Carrier and Spin Coherent Dynamics in Strained Germanium-Tin Semiconductor on Silicon
• Mid-infrared emission and absorption in strained and relaxed direct bandgap GeSn semiconductors
• Magneto-optical determination of the carrier lifetime in coherent Ge(1-x)Sn(x)/Ge heterostructures
• Photoluminescence study of interband transitions in few-layer, pseudomorphic, and strain-unbalanced Ge/GeSi multiple quantum wells