A5026810774- Photonic and Optical Devices
- Photonic Crystals and Applications
- Neural Networks and Reservoir Computing
- Advanced Fiber Optic Sensors
- Advanced Fiber Laser Technologies
- Advanced Photonic Communication Systems
- Nanowire Synthesis and Applications
- Mechanical and Optical Resonators
- Optical Network Technologies
- Thermal properties of materials
- Silicon Nanostructures and Photoluminescence
- Semiconductor materials and interfaces
- Advanced Thermoelectric Materials and Devices
- Thin-Film Transistor Technologies
Praevium Research (United States)
2025
Stanford University
2016-2019
Germanium–tin alloy nanowires hold promise as silicon-compatible optoelectronic elements with the potential to achieve a direct band gap transition required for efficient light emission. In contrast Ge1–xSnx epitaxial thin films, free-standing deposited on misfitting germanium or silicon substrates can avoid compressive, elastic strains that inhibit formation of gap. We demonstrate strong room temperature photoluminescence, consistent edge emission from both Ge core nanowires, elastically...
Whilst holding great promise for low noise, ease of operation and networking, useful photonic quantum computing has been precluded by the need beyond-state-of-the-art components, manufactured millions. Here we introduce a manufacturable platform with photons. We benchmark set monolithically-integrated silicon photonics-based modules to generate, manipulate, network, detect qubits, demonstrating dual-rail qubits $99.98\% \pm 0.01\%$ state preparation measurement fidelity, Hong-Ou-Mandel...
We study the effect of surface passivation on pseudomorphic multiple-quantum-well Ge0.97Sn0.03/Ge p-i-n photodetectors. A combination ozone oxidation to form GeOx and GeSnOx diodes followed by atomic layer deposition Al2O3 for protection these native oxides provides reduced dark current. With a temperature-dependent investigation current, we calculate activation energy be 0.26 eV at bias −0.1 V 0.05 −1 sample passivated this method. Based results, find that current is less dominated bulk...
The full exploration of Si-based photonic integrated circuits is limited by the lack an efficient light source that compatible with complementary metal–oxide–semiconductor process. Highly strained germanium (Ge) a promising solution, as its band structure can be fundamentally altered introducing tensile strain. However, main challenge lies in incorporation electrical while maintaining high strain uniform distribution active region. Here we present highly Ge LEDs driven lateral p–i–n...
We demonstrate tensile-strained pseudomorphic Ge0.934Sn0.066/Ge quantum wells in a microdisk resonator using silicon nitride stressor layers. The hydrostatic and biaxial strain distributions are studied through finite element modeling, while confocal Raman spectroscopy shows local transfers as high 1.1% at freestanding edges. These strains sufficient to overcome the original compressive Ge0.934Sn0.066 epitaxy reach direct band gap according deformation potential theory. A red-shift...
A high-quality Ge0.88Si0.08Sn0.04/Ge0.94Sn0.06 multiple quantum well (MQW) structure was grown on a Ge (001) substrate by sputtering epitaxy. The MQW characterized high-resolution x-ray diffraction and transmission electron microscopy. Surface-illuminated pin photodetectors were fabricated with cutoff wavelengths of up to 2140 nm. analysis transitions from spectral response fitted the theoretical calculations. Results suggest that epitaxy is promising method for preparing low-dimensional...
An efficient monolithically integrated laser on Si remains the missing component to enable photonics. We discuss design and fabrication of suspended tensile-strained Ge/SiGe multiple quantum well microdisk resonators for applications in photonics using an all-around SiNx stressor. etch-stop technique system is demonstrated allows capability removing defective buffer layer as providing precise thickness control resonators. Photoluminescence Raman spectroscopy indicate that we have achieved a...
Applying tensile strain with silicon nitride is demonstrated to improve the responsivity of germanium-tin (Ge <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</sub> Sn xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> ) PIN photodetectors at longer wavelengths. Such external stressor films show promise for extending application Ge optoelectronic devices into mid-infrared range.
Group-IV semiconductors have the opportunity to an equivalent or better temperature coefficient of resistance (TCR) than other microbolometer thermistor materials. By using multiple-quantum-well (MQW) structures, their TCR values can be optimized due a confinement carriers. Through two approaches – activation energy approximation and custom Monte Carlo transfer matrix method we simulated this effect for combination alloys (e.g., SiGe GeSn) find highest possible TCR, while keeping in mind...
Undercut design in a highly-stressed microdisk resonator cavity affects the magnitude and distribution of biaxial strain resonator, providing an additional approach to band-structure engineering. While wider undercut allows greater transfer, peak shifts away from edges where whispering gallery modes reside. With both considerations, we find that optimal 6 μm diameter Ge <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.934</sub> Sn...