Self-Organized Germanium Quantum Dots/Si₃N₄ Enabling Monolithic Integration of Top Si₃N₄-Waveguided Microdisk Light Emitters and p-i-n Photodetectors for On-Chip Sensing

Abstract

Using a coordinated combination of lithographic patterning and self-assembled growth, Ge spherical quantum dots (QDs) were controllably generated within host layers of Si 3 N 4 as active medium for Si photonics. A significant fabrication advantage of our approach is the high-temperature thermal stability of Ge QDs that are formed by thermal oxidation of poly-SiGe lithographically patterned structures at 800 • C-900 • C, offering flexibility in the waveguide (WG)-material choices, co-design, and integration of Ge photonic devices. Our Ge QDs enable monolithic integration of microdisk light emitters and p-i-n photodetectors (PDs) with top-Si 3 N 4 WG-coupled structures using standard Si processing. Low dark current of 0.3 mA/cm 2 at 300 K and 0.2 µA/cm 2 at 77 K in combination with 3-dB frequency of 12 GHz for Ge-QD PDs and low threshold power of 0.6 kW/cm 2 for optically pumped Ge QD/SiN microdisks light emission evidence the high degree of crystallinity of our Ge QDs being an effective building block for 3-D SiN photonic integrated circuits. Index Terms-Ge, microdisks, photodiodes (PDs), quantum dot (QD), top-Si 3 N 4 waveguides (WGs).

Enhancing Short-Wave Infrared Photosensitivity of SiGe Nanocrystals-Based Films through Embedding Matrix-Induced Passivation, Stress, and Nanocrystallization

“…Fabrication and characterization of properties of semiconductor nanomaterials, nanostructures and heterostructures (e.g., based on group IV Si, Ge, and Sn, emergent 2D transition metal dichalcogenides, Xene black phosphorus and graphdiyne, MXene, Se, Bi, and Te, CdS/CdSe) for applications in many fields ((opto)­electronics, (non)­linear photonics, spintronics and quantum computing, thermoelectrics, energy storage and conversion, catalysis, sensors, biomedical applications) are tackled in a great number of works. − Unique properties and enhanced device performance key for the development of nanoscience and nanotechnology have been highlighted. Emergent materials come with fascinating properties and prospect of wide range of versatile applications with remarkable device performance, but their study is still in its infancy and they present a lot of issues and challenges related to facile, low-cost, eco-friendly synthesis (at large scale) of high-quality nanostructures with targeted morphology and good stability under ambient conditions.…”