Communication Dans Un Congrès Année : 2026

Low-defect quantum dot lasers directly grown on silicon analyzed using cross-sectional scanning tunneling microscopy and spectroscopy

Résumé

Monolithic integration of III-V lasers on silicon is a central objective of silicon photonics, yet direct heteroepitaxy remains challenged by lattice and thermal-expansion mismatches that generate dislocations and other extended defects. Here we report an optimized molecular beam epitaxy (MBE) approach for InAs/InGaAs/GaAs quantumdot (QD) lasers directly grown on silicon, engineered to strongly suppress defect propagation toward the active region while preserving the electronic quality of the dot-in-a-well (DWELL) stack. We analyze the as-grown laser heterostructure using cross-sectional scanning tunneling microscopy and spectroscopy (X-STM/STS), which provides simultaneous atomic-scale structural information and energy-resolved access to the local density of states on the cleaved device cross section. Layer-by-layer STM imaging reveals the evolution of dislocations across dislocation filter layers, clarifies the role of the different filtering and smoothing stages, and confirms a very low density of extended defects in the vicinity of the active region. STS spectra measured on individual dots exhibit discrete confined states, and spatially resolved dI/dV mapping resolves the associated real-space wave function patterns. Using QD geometries extracted from STM, we implement finite-element modeling to compute confined electronic states and compare them quantitatively to the measured level spacings and wave function maps. Finally, ridge-waveguide lasers processed from the same wafer exhibit low threshold current and strong output power at elevated temperature, enabling a direct link between local STM/STS metrics, microscopic material quality, and device-scale laser performance.

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Dates et versions

hal-05597646 , version 1 (20-04-2026)

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  • HAL Id : hal-05597646 , version 1

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Konstantinos Papatryfonos, Jean-Christophe Girard, Mingchu Tang, Christophe David, Alwyn J. Seeds, et al.. Low-defect quantum dot lasers directly grown on silicon analyzed using cross-sectional scanning tunneling microscopy and spectroscopy. SPIE Photonics Europe, Apr 2026, Strasbourg, France. ⟨hal-05597646⟩
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