All Outputs (29)

Acoustic band engineering in terahertz quantum-cascade lasers and arbitrary superlattices (2023)
Journal Article

We present theoretical methods for the analysis of acoustic phonon modes in superlattice structures, and terahertz-frequency quantum-cascade lasers (THz QCLs). Our generalized numerical solution of the acoustic-wave equation provides good agreement w... Read More about Acoustic band engineering in terahertz quantum-cascade lasers and arbitrary superlattices.

Coherent Phononics of van der Waals Layers on Nanogratings (2022)
Journal Article

Strain engineering can be used to control the physical properties of two-dimensional van der Waals (2D-vdW) crystals. Coherent phonons, which carry dynamical strain, could push strain engineering to control classical and quantum phenomena in the unex... Read More about Coherent Phononics of van der Waals Layers on Nanogratings.

Luminescence and Crystalline Properties of InGaN-based LED on Si Substrate with AlN/GaN Superlattice Structure (2021)
Journal Article

A crack-free indium gallium nitride (InGaN) based light emitting diode (LED) grown on silicon (Si) substrate was successfully demonstrated by introducing aluminium nitride/gallium nitride (AlN/GaN) superlattice structure (SLS) in the growth of the LE... Read More about Luminescence and Crystalline Properties of InGaN-based LED on Si Substrate with AlN/GaN Superlattice Structure.

Nondestructive Picosecond Ultrasonic Probing of Intralayer and van der Waals Interlayer Bonding in α- and β-In2Se3 (2021)
Journal Article

The interplay between the strong intralayer covalent-ionic bonds and the weak interlayer van der Waals (vdW) forces between the neighboring layers of vdW crystals gives rise to unique physical and chemical properties. Here, the intralayer and interla... Read More about Nondestructive Picosecond Ultrasonic Probing of Intralayer and van der Waals Interlayer Bonding in α- and β-In2Se3.

Performance evaluation of a new 30 ?m thick GaAs X-ray detector grown by MBE (2021)
Journal Article

A circular mesa (400 μm diameter) GaAs p+-i-n+ photodiode with a 30 μm thick i layer was characterized for its performance as a detector in photon counting x-ray spectroscopy at 20 °C. The detector was fabricated from material grown by molecular beam... Read More about Performance evaluation of a new 30 ?m thick GaAs X-ray detector grown by MBE.

Low-energy switching of antiferromagnetic CuMnAs/GaP using sub-10 nanosecond current pulses (2020)
Journal Article

The recently discovered electrical-induced switching of antiferromagnetic (AF) materials that have spatial inversion asymmetry has enriched the field of spintronics immensely and opened the door for the concept of antiferromagnetic memory devices. Cu... Read More about Low-energy switching of antiferromagnetic CuMnAs/GaP using sub-10 nanosecond current pulses.

Temporal superoscillation of sub-terahertz coherent acoustic phonons (2020)
Journal Article

We observe coherent acoustic phonon superoscillations at sub-terahertz frequencies. The superoscillations result from the interference of optically excited coherent longitudinal acoustic phonon modes in a GaAs/AlGaAs superlattice. The superoscillatio... Read More about Temporal superoscillation of sub-terahertz coherent acoustic phonons.

Temporal superoscillations of subterahertz coherent acoustic phonons (2020)
Journal Article

We observe coherent acoustic phonon superoscillations at subterahertz frequencies. The superoscillations result from the interference of optically excited coherent longitudinal acoustic phonon modes in a GaAs/AlGaAs superlattice. The superoscillation... Read More about Temporal superoscillations of subterahertz coherent acoustic phonons.

Large non-thermal contribution to picosecond strain pulse generation using the photo-induced phase transition in VO2 (2020)
Journal Article

Picosecond strain pulses are a versatile tool for investigation of mechanical properties of meso-and nano-scale objects with high temporal and spatial resolutions. Generation of such pulses is traditionally realized via ultrafast laser excitation of... Read More about Large non-thermal contribution to picosecond strain pulse generation using the photo-induced phase transition in VO2.

High-speed modulation of a terahertz quantum cascade laser by coherent acoustic phonon pulses (2020)
Journal Article

The fast modulation of lasers is a fundamental requirement for applications in optical communications, high-resolution spectroscopy and metrology. In the terahertz-frequency range, the quantum-cascade laser (QCL) is a high-power source with the poten... Read More about High-speed modulation of a terahertz quantum cascade laser by coherent acoustic phonon pulses.

30 μm thick GaAs X-ray p + -i-n + photodiode grown by MBE (2019)
Journal Article

7 8 A GaAs p +-in + photodiode detector with a 30 μm thick i layer and a 400 μm diameter was processed using 9 standard wet chemical etching from material grown by molecular beam epitaxy. The detector was 10 characterized for its electrical and photo... Read More about 30 μm thick GaAs X-ray p + -i-n + photodiode grown by MBE.

High-Frequency Elastic Coupling at the Interface of van der Waals Nanolayers Imaged by Picosecond Ultrasonics (2019)
Journal Article

Although the topography of van de Waals (vdW) layers and heterostructures can be imaged by scanning probe microscopy, high-frequency interface elastic properties are more difficult to assess. These can influence the stability, reliability and perform... Read More about High-Frequency Elastic Coupling at the Interface of van der Waals Nanolayers Imaged by Picosecond Ultrasonics.

Ultrafast insulator-metal transition in VO2 nanostructures assisted by picosecond strain pulses (2019)
Journal Article

Strain engineering is a powerful technology that exploits the stationary external or internal stress of specific spatial distribution for controlling the fundamental properties of condensed materials and nanostructures. This advanced technique modula... Read More about Ultrafast insulator-metal transition in VO2 nanostructures assisted by picosecond strain pulses.

Resonance of terahertz phonons in an acoustic nanocavity (2018)
Journal Article

We show the resonant behavior of ∼0.5-THz longitudinal acoustic (LA) phonons in an acoustic nanocavity of thickness ∼28 nm sandwiched between two GaAs/AlAs superlattices (SLs). One of the SLs, upon excitation with an ultrafast optical pulse, acts as... Read More about Resonance of terahertz phonons in an acoustic nanocavity.

A high electron mobility phonotransistor (2018)
Journal Article

Acoustoelectric devices convert acoustic energy to electrical energy and vice versa. Devices working at much higher acoustic frequencies than those currently available have potential scientific and technological applications, e.g.: as detectors in ph... Read More about A high electron mobility phonotransistor.

Coherent acoustic phonons in van der Waals nanolayers and heterostructures (2018)
Journal Article

Terahertz (THz) and sub-THz coherent acoustic phonons have been successfully used as probes of various quantum systems. Since their wavelength is in the nanometer range, they can probe nanostructures buried below a surface with nanometer resolution a... Read More about Coherent acoustic phonons in van der Waals nanolayers and heterostructures.

Photoelastic properties of zinc-blende (AlGa)N in the UV: picosecond ultrasonic studies (2018)
Journal Article

Picosecond ultrasonics was used to study the photoelastic properties of zinc-blende (cubic) c-Al?Ga???N with x around 0.5 The velocities for longitudinal sound in the alloys were measured using ultrafast UV pump-probe experiments with (Al... Read More about Photoelastic properties of zinc-blende (AlGa)N in the UV: picosecond ultrasonic studies.

Phonon spectroscopy with chirped shear and compressive acoustic pulses (2017)
Journal Article

Picosecond duration compressive and shear phonon wave packets injected into (311) GaAs slabs transform after propagation through ?1??mm into chirped acoustic pulses with a frequency increasing in time due to phonon dispersion. By probing the temporal... Read More about Phonon spectroscopy with chirped shear and compressive acoustic pulses.

Molecular beam epitaxy as a growth technique for achieving free-standing zinc-blende GaN and wurtzite AlxGa1-xN (2017)
Journal Article

Currently there is a high level of interest in the development of ultraviolet (UV) light sources for solid state lighting, optical sensors, surface decontamination and water purification. III-V semiconductor UV LEDs are now successfully manufactured... Read More about Molecular beam epitaxy as a growth technique for achieving free-standing zinc-blende GaN and wurtzite AlxGa1-xN.

Piezoelectric response to coherent longitudinal and transverse acoustic phonons in a semiconductor Schottky diode (2017)
Journal Article

We study the generation of microwave electronic signals by pumping a (311) GaAs Schottky diode with compressive and shear acoustic phonons, generated by femtosecond optical excitation of an Al _lm transducer and mode conversion at the Al-GaAs interfa... Read More about Piezoelectric response to coherent longitudinal and transverse acoustic phonons in a semiconductor Schottky diode.