A5063052986- Photonic and Optical Devices
- Advanced Photonic Communication Systems
- Semiconductor Lasers and Optical Devices
- Semiconductor Quantum Structures and Devices
- Nanowire Synthesis and Applications
- Advanced Semiconductor Detectors and Materials
- Advanced Fiber Optic Sensors
- Thin-Film Transistor Technologies
- Photonic Crystals and Applications
- Semiconductor materials and interfaces
- Neutrino Physics Research
- Silicon Nanostructures and Photoluminescence
- Astrophysics and Cosmic Phenomena
- Spectroscopy and Laser Applications
- Chalcogenide Semiconductor Thin Films
- Semiconductor materials and devices
- Quantum Dots Synthesis And Properties
- Optical Network Technologies
- Optical Coatings and Gratings
- Dark Matter and Cosmic Phenomena
- Radiation Detection and Scintillator Technologies
- Advanced Optical Sensing Technologies
- Particle Detector Development and Performance
- Phase-change materials and chalcogenides
- Neural Networks and Reservoir Computing
United States Air Force Research Laboratory
2020-2024
University of Arkansas at Fayetteville
2011-2021
Sandia National Laboratories
2021
Applied Technology Associates (United States)
2020-2021
Arizona State University
2020-2021
New Mexico State University
2021
Wilkes University
2018-2021
The University of Texas at Austin
2020
University of New Mexico
2020
University of Massachusetts Boston
2018
The GeSn detector offers high-performance Si-based infrared photodetectors with complementary metal-oxide-semiconductor (CMOS) technique compatibility. In this work, we report a comprehensive study of mid-infrared photodetectors, which includes the demonstration set photoconductors Sn compositions ranging from 10.5% to 22.3%, showing cutoff wavelength has been extended 3.65 μm. maximum D* 1.1 × 1010 cm·Hz1/2·W–1 measured at 77 K is comparable that commercial extended-InGaAs detectors. We...
A Si-based monolithic laser is strongly desired for the full integration of Si-photonics. Lasing from direct bandgap group-IV GeSn alloy has opened a new avenue, different hybrid III–V-on-Si approach. We demonstrated optically pumped lasers on Si with broad wavelength coverage 2 to 3 μm. The alloys were grown using newly developed approaches an industry standard chemical vapor deposition reactor and low-cost commercially available precursors. achieved maximum Sn composition 17.5% exceeded...
Abstract Recent development of group-IV alloy GeSn indicates its bright future for the application mid-infrared Si photonics. Relaxed with high material quality and Sn composition is highly desirable to cover wavelength. However, crystal growth remains a great challenge. In this work, systematic study strain relaxation mechanism effects on incorporation during via chemical vapor deposition was conducted. It discovered that into Ge lattice sites limited by compressive rather than historically...
Low-cost shortwave infrared detectors have great potential for emerging civilian night-vision applications. This paper reports the characteristics of Ge0.89Sn0.11 photodiodes monolithically grown on a Si substrate that holds promise those At room temperature, 500 μm diameter active area device demonstrated longwave cutoff 2.65 and responsivity 0.32 A/W at 2 μm, which corresponds to an external quantum efficiency 20% without any contribution from Ge buffer layer. The measured peak specific...
In this work, all group-IV band-to-band lasers based on SiGeSn/GeSn/SiGeSn multi-quantum-well structures were demonstrated. Lasing performance was investigated via two 4-well samples. The thinner GeSn well sample exhibits a maximum lasing temperature of 20 K and threshold 55 kW/cm2 at 10 K, while the thicker features higher operating 90 lower thresholds 25 62 77 respectively. distinct results tentatively interpreted mainly by difference gain volume. This result provides guidance for future...
The persistent interest of the epitaxy group IV alloy GeSn is mainly driven by demand for an efficient light source that could be monolithically integrated on Si mid-infrared photonics. For chemical vapor deposition GeSn, exploration growth window difficult from beginning due to metastable nature material requiring non-equilibrium condition. In this work, we demonstrated effective pathway achieve high quality with levels Sn incorporation. films were grown Ge-buffered via ultra-high vacuum...
The semiconductor minority carrier lifetime contains information about several important material properties, including Shockley–Read–Hall defect levels/concentrations and radiative/Auger recombination rates, the complex relationships between these parameters produce a non-trivial temperature-dependence of measured lifetime. It is tempting to fit temperature-dependent data extract properties centers; however, without priori knowledge distribution states across bandgap, this problem...
We report room-temperature Raman scattering studies of nominally undoped (100) GaAs 1-x Bi x epitaxial layers exhibiting Biinduced (p-type) longitudinal-optical-plasmon-coupled (LOPC) modes for 0.018 ≤ 0.048.Redshifts in the GaAs-like optical due to alloying are evaluated and paralleled by strong damping LOPC.The relative integrated intensities LO(Γ) LOPC A LO /A characteristic heavily doped p-GaAs, with a remarkable near total screening phonon (A → 0) larger concentrations.A method spectral...
Gallium is incorporated into the strain-balanced In(Ga)As/InAsSb superlattice system to achieve same mid-wave infrared cutoff tunability as conventional Ga-free InAs/InAsSb type-II superlattices, but with an additional degree of design freedom enable optimization absorption and transport properties. Time-resolved photoluminescence measurements InGaAs/InAsSb characterization- doped device structures are reported from 77 300 K compared InAs/InAsSb. The low-injection decay yields minority...
GaAsBi/GaAs double quantum wells and well separate confinement heterostructures are grown at low temperatures using molecular beam epitaxy. Methods of achieving identical in structures without growth interruption proposed implemented. Cross-sectional transmission electron microscopy room temperature photoluminescence measurements indicate that the samples have excellent structural optical properties. The high quality is attributed to surfactant effect Bi throughout GaAs AlGaAs layers....
This paper reports the comprehensive characterization of a Ge0.92Sn0.08/Ge0.86Sn0.14/Ge0.92Sn0.08 single quantum well. By using strain relaxed Ge0.92Sn0.08 buffer, direct bandgap Ge0.86Sn0.14 QW was achieved, which is unattainable by only Ge buffer. Band structure calculations and optical transition analysis revealed that well features type-I band alignment. The photoluminescence spectra showed dramatically increased peak intensity at lower temperature, confirming material.
Single crystalline GeSn growth on Si substrate was successfully demonstrated by using plasma enhanced chemical vapor deposition (PE-CVD) with commercially available GeH4 and SnCl4 precursors. Using the enhancement technique, low temperature at 350°C for epitaxy achieved rate of 51.4 nm/min Sn content up to 6%. The relaxed films 1 µm thickness were able be grown despite huge lattice mismatch between Si. Structural optical characterizations conducted study film properties. showed its...
A minority carrier lifetime of 2.7 ns is measured at 77 K for a GeSn/SiGeSn single quantum well using time-resolved photoluminescence, and subsequent analyses indicate that the Auger-limited. The evaluated as function stepwise dose 63 MeV proton irradiation up to fluence 1.5 × 1012 p+/cm2 with no discernable reduction in observed lifetime, which implies damage factor slope not greater than 2 10−5 cm2/s. Steady-state photoluminescence used evaluate total luminescence output excitation,...
The effect of rapid thermal annealing on the optical and structural properties GaAsBi/GaAs quantum wells (QWs) is investigated. photoluminescence (PL) spectra samples are measured at 80 K room temperature before after annealing, to ascertain any improvement in quality material. impact QW interface quality, layer composition, thicknesses studied with x-ray diffraction. For a 60 second time, low peak PL intensity increases maximum 1.8 times original an 500 °C. Validating this optimum...
InAsSbBi nBn photodetectors are demonstrated that lattice-matched to the underlying GaSb substrate with a 4.32 μm wavelength cutoff at 150 K is 0.3 longer than of InAsSb this temperature reflecting 0.5% Bi mole fraction in active region. A low growth was utilized facilitate incorporation Bi, resulting minority carrier lifetime on order 24 ns Nevertheless, detectors exhibit quantum efficiency 17% 3.3 dark current density 50 μA/cm2 and −0.4 V bias strong photoresponse turn-on characteristic...
The GeSn-based quantum wells (QWs) have been investigated recently for the development of efficient GeSn emitters. Although our previous study indicated that direct bandgap well with type-I band alignment was achieved, demonstrated QW still has insufficient carrier confinement. In this work, we report systematic light emission from Ge0.91Sn0.09/Ge0.85Sn0.15/Ge0.91Sn0.09 double structure. Two samples, thicknesses Ge0.85Sn0.15 6 and 19 nm, were investigated. Band structure calculations...
Quinary GaInAsSbBi is grown by molecular beam epitaxy, and the alloy demonstrated with a bandgap energy of 291 meV (λcutoff ∼ 4.3 μm) minority carrier lifetime 0.34 μs at 120 K. The epilayer to thickness 1 μm 400 °C lattice-matched GaSb substrate Bi mole fraction 0.13% measured Rutherford backscattering spectroscopy. Steady-state time-resolved photoluminescence measurements are performed gauge comparative bandgaps optical quality as well InAsSbBi GaInAsSb reference samples. A recombination...
The recent progress on (Si)GeSn optoelectronic devices holds a great promising for photonic integration the Si substrate. In parallel to development of bulk devices, based quantum wells (QWs) have been investigated aiming improve device performance. While multiple QW structure is preferred application, single well (SQW) more suitable optical property study. this work, comprehensive study SiGeSn/GeSn SQW was conducted. calculated band diagram provided alignment and energies possible...
Silicon germanium tin alloys were grown directly on Si substrates using a cold-wall ultrahigh-vacuum chemical vapor deposition system at 300 °C, where commercially available precursors of silane, germane, and stannic chloride used to grow the epitaxial layers. The crystallinity growth quality SiyGe1−x−ySnx films investigated through material characterization methods including x-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy, transmission microscopy. Rutherford...
Dilute GeSn films have been grown at the temperatures below 400 °C in a cold-walled ultrahigh vacuum chemical-vapor-deposition chamber. Diluted tin-tetrachloride (SnCl4) with flow rate of 0.02 sccm was used as Sn precursor while Ge germane 10 sccm. For comparison, were under same conditions except only used. Material growth study revealed linear rates for both and increased nucleation times lower temperatures. optical characterizations showed that featured longer times, higher rates, crystal...
Time-resolved photoluminescence measurements are reported for InAsSbBi alloys grown by molecular beam epitaxy with Bi mole fractions ranging from 0 to 0.8%, yielding minority carrier lifetimes on the order of hundreds nanoseconds. The extracted time-resolved comparable those lattice-matched InAsSb at same respective temperatures. Nomarski imaging shows that smooth, droplet-free surface morphologies obtained in 1 μm thick epilayers temperatures between 360 and 380 °C. alloy...