A5031707805- Semiconductor Quantum Structures and Devices
- Advanced Semiconductor Detectors and Materials
- Quantum and electron transport phenomena
- Advancements in Semiconductor Devices and Circuit Design
- Semiconductor Lasers and Optical Devices
- Spectroscopy and Laser Applications
- Semiconductor materials and devices
- Solid State Laser Technologies
- Electronic and Structural Properties of Oxides
- Surface and Thin Film Phenomena
- Chalcogenide Semiconductor Thin Films
- Photonic and Optical Devices
- Physics of Superconductivity and Magnetism
- Nanowire Synthesis and Applications
- Thermal properties of materials
- Molecular Junctions and Nanostructures
- Photorefractive and Nonlinear Optics
- Thermal Radiation and Cooling Technologies
- Laser Design and Applications
- Advanced Fiber Laser Technologies
- Advanced Thermoelectric Materials and Devices
- Force Microscopy Techniques and Applications
- Diamond and Carbon-based Materials Research
- Advanced Mathematical Theories and Applications
- Electrochemical Analysis and Applications
Huainan Normal University
2023-2024
United States Naval Research Laboratory
1998-2010
Sarcoma Foundation of America
1992
Spin injection at a ferromagnet-semiconductor interface is observed by projecting the spin-polarized current in ferromagnet onto spin-split density of states high mobility two-dimensional electron gas (2DEG). For given polarization carriers 2DEG, reversing magnetization orientation modulates resistance. Equivalently, 2DEG bias polarity gives same resistance modulation. Interface changes order 1% room temperature indicate interfacial polarizations 20%.
InAs/GaSb composite quantum wells sandwiched by AlSb are studied using capacitance-voltage, Hall, and three-terminal transfer measurements. Our data reveal a positive energy gap resulting from the hybridization of in-plane dispersions electrons in InAs holes GaSb for conventionally recognized ``semimetallic'' heterostructures.
Two different approaches, a photoconductive response technique and correlation of lasing thresholds with theoretical threshold carrier concentrations have been used to determine Auger lifetimes in InAs/GaInSb quantum wells. For energy gaps corresponding 3.1–4.8 μm, the room-temperature coefficients for seven samples are found be nearly an order-of-magnitude lower than typical type-I results same wavelength. The data imply that at this temperature, rate is relatively insensitive details band...
In this paper, we define h-Shuhan matrix, which is the generalization of generalized Cartan and find matrices for all positive semi-definite ( or semi-definite, virtual semi-definite) with $h<2$. Furthermore, know that largest eigenvalue matrix $\hat{B}_{n}^{h}$ increases $n$, but it always less than $h$ plus a constant $\epsilon\approx2.04998$.
Optically pumped type-II W lasers emitting in the mid-infrared exhibited continuous-wave (cw) operating temperatures of 290 K at λ=3.0 μm and 210 λ=6.1 μm. Maximum cw output powers for 78 were 260 mW λ=3.1 nearly 50 λ=5.4 These high maximum achieved through use a diamond-pressure-bonding technique heat sinking semiconductor lasers. The thermal bond, which is accomplished pressure alone, permits topside optical pumping diamond wavelengths that would be absorbed by substrate.
We report temperature-dependent pulsed lasing performance, internal losses, and Auger coefficients for optically pumped type-II W lasers with wavelengths in the range of 3.08–4.03 μm at room temperature. All lased to least 360 K, produced 1.5–5 peak power 300 K. Internal losses 100 K were as low 10 cm−1, but increased 90–360 cm−1 Room temperature varied from 5×10−28 cm6/s shortest wavelength 3×10−27 longest.
We report the observation of spin-doublet splitting cyclotron resonance (CR) in a two-dimensional electron gas (2DEG). Two discernible CR peaks, originating from spin-conserved transitions between adjacent sets spin-split Landau states, are observed at magnetic field as low 4.4 T. The doublet features vicinity even and odd integer filling factors attributed to linear dependence g factor effective mass on energy, respectively. In addition, our data show that 2DEG has smaller energy than bulk...
A differential 3ω technique is employed to determine the thermal conductivity of AlAs0.07Sb0.93 ternary alloy, Al0.9Ga0.1As0.07Sb0.93 quaternary and an (AlAs)1/(AlSb)11 digital-alloy superlattice. Between 80 300 K, conductivities for all three samples are relatively insensitive temperature. The superlattice smaller than that but much larger predictions a model phonon transport across interfaces.
The effect of interface bond configuration on the structural and optical properties short-period ( approximately=50 AA) GaSb/InAs superlattices has been examined. Structures consisting eight monolayers GaSb seven InAs with either 'GaAs-like' or 'InSb-like' bonds were grown by MBE. Evidence for differences in properties, vibrational band structure two types material was obtained using X-ray diffraction, Raman scattering, interband magneto-absorption photoconductivity measurements.
A Reply to the Comment by F. G. Monzon, H. X. Tang, and M. L. Roukes, also B. J. van Wees.Received 9 December 1999DOI:https://doi.org/10.1103/PhysRevLett.84.5024©2000 American Physical Society
The spin-resolved cyclotron resonance of a two-dimensional electron gas in an InAs quantum well sandwiched by AlSb barriers has been investigated to determine the energy dependence effective mass. We observe variations mass correlated with filling factor due linear and Land\'e g on energy. experimental results are analyzed envelope-function approximation under four-band k\ensuremath{\cdot}p model which leads renormalized well. Excellent agreement experiment is achieved we able conclude that...
The authors have studied the molecular-beam epitaxial growth of type-II heterostructures for mid-wavelength infrared lasers. Based on their photoluminescence spectra and X-ray diffraction patterns, it is found that quality these highly sensitive to temperature interfacial bond type.
Forming solid solutions is one of the most effective strategies to suppress thermal conductivity thermoelectric materials. However, accompanying increase in impurity ion scattering usually results an undesirable loss hall mobility, negatively impacting electrical transport properties. In this work, a tellurium-selenium (Te-Se) solution with trace antimony (Sb) doping was synthesized via high pressure and temperature method. It found that slight Se into Te sites not only had no impact on...
The surface, structural, and optical properties of InAs/InGaSb/AlSb mid-infrared lasers grown by molecular beam epitaxy have been systematically studied, respectively, Nomarski differential interference contrast, high-resolution x-ray diffraction, variable-temperature photoluminescence. It is found that the optimum growth temperature between 400 450 °C, based on calibrated transmission thermometry. In addition, impact interfacial bond type Sb sources has investigated. A 5.91 μm laser, with...
AlSb/InAs HEMTs with a 0.1 µm gate length have been fabricated thin InAs subchannel separated from the channel by 30 Å of AlSb. As result, these exhibit improved charge control and higher current-gain cutoff frequency. The devices microwave transconductance 850 mS/mm an fT 180 GHz at VDS = 0.6 V. After subtracting bonding pad capacitance, 250 was obtained.
The authors review recent demonstrations of improved mid-IR laser performance when a type II 'W-well' structure is incorporated into the active region. W configuration consists hole quantum well (e.g. GaSb or GaInSb) between electron wells InAs) in order to maximise gain while suppressing nonradiative Auger losses. Optically pumped lasers recently produced more than 1.4 per facet peak power for pulsed operation at 300 K. An interband cascade with region (W-ICL) has operated up 286 first...
Sheet carrier concentrations in quantum wells of InAs clad by AlSb were enhanced modulation doping with very thin (9–12 Å) remote InAs(Si) donor layers. The growth temperature the layers was a key parameter, relatively low temperatures required to minimize Si segregation into AlSb. as high 3.2×1012/cm2 and 5.6×1012/cm2 achieved single- double-sided doping, respectively. High electron mobility transistors fabricated using doped structure exhibited unity current gain cut-off frequency 60 GHz...
The far-field emission characteristics of mid-infrared angled-grating distributed-feedback (α-DFB) lasers with W active regions are calculated using a self-consistent beam-propagation formalism that is more general than previous analyses. theoretical projections compared the results an experimental study optically pumped α-DFB devices. Near-diffraction-limited beam quality obtained both theoretically and experimentally for pump stripes ⩽50 μm wide. While simulations employing linewidth...
We report near-diffraction-limited output from an angled-grating distributed feedback type-II W laser emitting near 3.4 μm. For pulsed optical pumping of a 50-μm-wide stripe at 78 K, the far-field beam divergence angle was only 1.4°. The slope efficiency 64% that for conventional Fabry–Pérot on same bar. However, spectral linewidth decreased by factor 2. quality substantially better than out to widths least 800
We describe an optical pumping injection cavity (OPIC) edge-emitting laser which employs GaSb/AlAsSb distributed Bragg reflectors above and below the type-II “W” active region to form etalon for pump beam. A pulsed W–OPIC emitting at 3.1–3.4 μm displays incident threshold intensity of only 8 kW/cm2 300 K, power conversion efficiencies per facet 9% 77 K 4% 275 K.