Oussama Moutanabbir

Polytechnique Montréal · Department of Engineering Physics

It addition to its high evaporation field, diamond is also known for its limited photoabsorption, strong covalent bonding, and wide bandgap. These characteristics have been thought for long to also complicate the field evaporation of diamond and make its control hardly achievable on the atomistic-level. Herein, we demonstrate that the unique behavi...

The introduction of stable isotopes in the fabrication of semiconductor nanowires provides an additional degree of freedom to manipulate their basic properties, design an entirely new class of devices, and highlight subtle but important nanoscale and quantum phenomena. With this perspective, we report on phonon engineering in metal catalyzed silico...

Strain engineering is ubiquitous in design and fabrication of innovative, high-performance electronic, optoelectronic, and photovoltaic devices. The increasing importance of strain-engineered nanoscale materials has raised significant challenges at both fabrication and characterization levels. Raman Scattering Spectroscopy (RSS) is one of the most...

Coherent X-ray diffraction imaging (CDI) has emerged in the last decade as a promising high resolution lens-less imaging approach for the characterization of various samples. It has made significant technical progress through developments in source, algorithm and imaging methodologies thus enabling important scientific breakthroughs in a broad rang...

Sn-containing group IV semiconductors create the possibility to independently control strain and band gap thus providing a wealth of opportunities to develop an entirely new class of low dimensional systems, heterostructures, and silicon-compatible electronic and optoelectronic devices. With this perspective, this work presents a detailed investiga...

Transferring energy without transferring mass is a powerful paradigm to address the challenges faced when the access to, or the deployment of, the infrastructure for energy conversion is locally impossible or impractical. Laser beaming holds the promise of effectively implementing this paradigm. With this perspective, this work evaluates the optica...

Achieving high crystalline quality germanium‐tin (Ge1 − xSnx) semiconductors at Sn content exceeding 10% is quintessential to implement the long sought‐after silicon‐compatible mid‐infrared photonics. Herein, by using sub‐20 nm Ge nanowires as compliant growth substrates, Ge1 − xSnx alloys with a Sn content of 18% exhibiting a high composition unif...

There is an increasing need for silicon-compatible high-bandwidth extended-short wave infrared (e-SWIR) photodetectors (PDs) to implement cost-effective and scalable optoelectronic devices. These systems are quintessential to address several technological bottlenecks in detection and ranging, surveillance, ultrafast spectroscopy, and imaging. In fa...

The complex relative permittivity of doped Ge1−xSnx thin films (realized using state-of-the-art growth techniques) are obtained by devising a methodology based upon polarization-dependent reflection measurements along with multi-layer Fresnel reflection equations. The developed approach is implemented to acquire the complex relative permittivity of...

The p‐symmetry of the hole wavefunction is associated with a weaker hyperfine interaction, which makes hole spin qubits attractive candidates for quantum processors. However, recent studies demonstrated that hole qubits are still very sensitive to nuclear spin bath, thus highlighting the need for nuclear spin‐free Ge qubits to suppress this decoher...

Ge1−xSnx semiconductors have promise for large-scale, monolithic, midinfrared photonics and optoelectronics. However, despite the successful demonstration of several Ge1−xSnx-based photodetectors and emitters, key fundamental properties of this material system are yet to be fully explored and understood. In particular, little is known about the rol...

The parallels between terahertz time-domain spectroscopy (THz-TDS) and discrete Fourier transform spectroscopy (DFTS) are unraveled by showing that the same Fresnel equation links the optical properties of a material to measurements obtained using either approach. Such similarities are revealed by evaluating this same Fresnel equation incorporating...

Compound semiconductors have been the predominant building blocks for the current midinfrared thermophotovoltaic devices relevant to sub- $2000 \,\mathrm{K}$ heat conversion and power beaming. However, the prohibitively high cost associated with these technologies limits their broad adoption. Herein, to alleviate this challenge we introduce an all...

Nanowires are promising platforms for realizing ultra-compact light sources for photonic integrated circuits. In contrast to impressive progress on light confinement and stimulated emission in III-V and II-VI semiconductor nanowires, there has been no experimental demonstration showing the potential to achieve strong cavity effects in a bottom-up g...

The p-symmetry of the hole wavefunction is associated with a weaker hyperfine interaction as compared to electrons, thus making hole spin qubits attractive candidates to implement long coherence quantum processors. However, recent studies demonstrated that hole qubits in planar germanium (Ge) heterostructures are still very sensitive to nuclear spi...

With the utilization of Fourier-transform infrared (FTIR) spectroscopy for a multitude of commercial applications, a robust methodology for designing, implementing, and servicing these systems in commercial settings is becoming increasingly paramount. Here we present a method allowing for the numerical evaluation of the interferogram signal in a FT...

The short-wave infrared (SWIR) is an underexploited portion of the electromagnetic spectrum in metasurface-based nanophotonics despite its strategic importance in sensing and imaging applications. This is mainly attributed to the lack of material systems to tailor light-matter interactions in this range. Herein, we address this limitation and demon...

The highly-nonlinear chalcopyrite crystal family has experienced remarkable success as source crystals in the mid-infrared spectral range, such that these crystals are primary candidates for producing high terahertz frequency (i.e., ≳\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \...

The optical injection of charge and spin currents is investigated in Ge1−xSnx semiconductors as a function of Sn content. These emerging silicon-compatible materials enable the modulation of these processes across the entire mid-infrared range. Under the independent-particle approximation, the one- and two-photon interband absorption processes are...

The selective confinement of light holes (LHs) is demonstrated by introducing a low-dimensional system consisting of a highly tensile-strained Ge quantum well enabling the design of an ultrafast gate-defined spin qubit under the electric dipole spin resonance. The qubit size-dependent g factor and dipole moment are mapped, and the parameters induci...

A phase-resolved electric field pulse is produced through the second-order nonlinear process of intra-pulse difference frequency generation (DFG) in a (110) CdSiP2 chalcopyrite crystal. The generated electric field pulse exhibits a duration of several picoseconds and contains frequency components within the high-frequency terahertz regime of ∼17–32...

Compound semiconductors have been the predominant building blocks for the current mid-infrared thermophotovoltaic devices relevant to sub-2000 K heat conversion and power beaming. However, the prohibitively high cost associated with these technologies limits their broad adoption. Herein, to alleviate this challenge we introduce an all-group IV mid-...

Ge$_{1-x}$Sn$_x$ semiconductors hold the premise for large-scale, monolithic mid-infrared photonics and optoelectronics. However, despite the successful demonstration of several Ge$_{1-x}$Sn$_x$-based photodetectors and emitters, key fundamental properties of this material system are yet to be fully explored and understood. In particular, little is...

Continued development in the areas of communication, security, medicine, and safety is calling for terahertz‐wave technologies to evolve beyond laboratory research and into the realm of real‐world applications. Due to the compatibility of waveguides with on‐chip fabrication techniques and their ability to realize a small footprint, such structures...

Monolithic integration of extended short-wave infrared photodetectors (PDs) on silicon is highly sought-after to implement manufacturable, cost-effective sensing and imaging technologies. With this perspective, GeSn PIN PDs have been the subject of extensive investigations because of their bandgap tunability and silicon compatibility. However, due...

A GaSe crystal cut along the (001) crystallographic plane is investigated for the emission and detection of high-frequency (i.e. up to ∼20 THz) electric fields. To date, a comprehensive analysis on high-frequency difference frequency generation and electro-optic sensing in GaSe has not been performed and should consider aspects such as electric fie...

High-frequency terahertz radiation detection is experimentally investigated via electro-optic sampling in a CdSiP 2 crystal, while high terahertz frequency generation is experimentally considered via difference frequency generation in ZnGeP 2 and CdSiP 2 crystals.

Experimental measurements are conducted to investigate optical rectification generation and electro-optic detection in pnictide and chalcogenide ternary crystals at frequencies below ~3 THz.

Electron spins in Si/SiGe quantum wells suffer from nearly degenerate conduction band valleys, which compete with the spin degree of freedom in the formation of qubits. Despite attempts to enhance the valley energy splitting deterministically, by engineering a sharp interface, valley splitting fluctuations remain a serious problem for qubit uniform...

The optical injection of charge and spin currents are investigated in Ge$_{1-x}$Sn$_{x}$ semiconductors as a function of Sn content. These emerging silicon-compatible materials enable the modulation of these processes across the entire mid-infrared range. Under the independent particle approximation, the one- and two-photon interband absorption pro...

The short-wave infrared (SWIR) is an underexploited portion of the electromagnetic spectrum in metasurface-based nanophotonics despite its strategic importance in sensing and imaging applications. This is mainly attributed to the lack of material systems to tailor light-matter interactions in this range. Herein, we address this limitation and demon...

Atom probes generate three‐dimensional atomic‐scale tomographies of material volumes corresponding to the size of modern‐day solid‐state devices. Here, the capabilities of atom probe tomography are evaluated to analyze buried interfaces in semiconductor heterostructures relevant for electronic and quantum devices. Employing brute‐force search, the...

A true monolithic infrared photonics platform is within reach if strain and bandgap energy can be independently engineered in SiGeSn semiconductors. Herein, we investigate the structural and optoelectronic properties of a 1.5 μm-thick Si 0.06 Ge 0.90 Sn 0.04 layer that is nearly lattice-matched to a Ge on Si substrate. Atomic-level studies demonstr...

The selective confinement of light-holes (LHs) is demonstrated by introducing a low-dimensional system consisting of highly tensile-strained Ge quantum well enabling the design of an ultrafast gate-defined spin qubit under the electric dipole spin resonance. The qubit size-dependent $g$-factor and dipole moment are mapped, and the parameters induci...

Ge/SiGe multi-quantum well heterostructures are highly sought-after for silicon-integrated optoelectronic devices operating in the broad range of the electromagnetic spectrum covering infrared to terahertz wavelengths. However, the epitaxial growth of these heterostructures at a thickness of a few micrometers has been a challenging task due to the...

With the numerous recent demonstrations of germanium-tin (GeSn) semiconductor lasers, this material has become the strongest candidate for the realization of photonic-integrated circuits (PICs). However, the high defect density of this material often results in high lasing thresholds, making them undesirable for real-world applications. Furthermore...

GeSn alloys have been regarded as a promising material for creating a complementary metal-oxide-semiconductor (CMOS)-compatible light source. Despite the remarkable progress in demonstrating GeSn lasers, an unavoidable intrinsic compressive strain introduced during epitaxial growth has prevented researchers from pushing the directness of GeSn gain...

GeSn alloys have emerged as a promising material for group IV light sources because alloying Ge with Sn increases the directness of the bandstructure, thus improving the efficiency of light emission. Despite several years of progress in GeSn lasers, however, the integration of such lasers into practical applications still faces challenges such as h...

Achieving coherent optical photon-to-spin conversion is a long-sought-after strategy for surmounting current fundamental limits in optical schemes that hinder the long-distance distribution of entanglement. Moreover, photon-to-spin interfaces are also essential for a direct mapping of the quantum information encoded in photon flying qubits to stati...

The last decade has witnessed explosive growth in terahertz radiation fields, ranging from fundamental research to applications. This progress has been marked by the introduction of various terahertz radiation sources and detectors. Here, we review the progress of nonlinear pnictide and chalcogenide ternary crystals for use in the terahertz frequen...

Interfaces are ubiquitous in semiconductor low-dimensional systems used in electronics, photonics, and quantum computing. Understanding their atomic-level properties has thus been crucial to controlling the basic behavior of heterostructures and optimizing the device performance. Herein, we demonstrate that subnanometer interfacial broadening in he...

Nanowires are promising platforms for realizing ultra-compact light sources for photonic integrated circuits. In contrast to impressive progress on light confinement and stimulated emission in III-V and II-VI semiconductor nanowires, there has been no experimental demonstration showing the potential to achieve strong cavity effects in a bottom-up g...

With their ns ² np ³ electron configuration and sp ³ hybridization, pnictogens (N, P, As, Sb, Bi) form a unique class of elemental van der Waals (vdW) and two-dimensional (2D) materials. The layered allotropes and the wide range of atomic masses span by pnictogens endows them with a broad spectrum of electronic, optical, and topological properties....

We present our latest results on GeSn laser technologies, including high-quality GeSn-on-insulator substrates and improved microdisk and nanobeam GeSn lasers.

The quiet quantum environment of holes in solid‐state devices has been at the core of increasingly reliable architectures for quantum processors and memories. However, due to the lack of scalable materials to properly tailor the valence band character and its energy offsets, the precise engineering of light‐hole (LH) states remains a serious obstac...

GeSn alloys are a promising emerging complementary metal–oxide–semiconductor compatible technology for applications in photonics and electronics. However, the unavoidable intrinsic compressive strain introduced during epitaxial growth has prevented researchers from pushing the performance of GeSn devices to the limit and realizing real-world applic...

Ge/SiGe multi-quantum well heterostructures are highly sought-after for silicon-integrated optoelectronic devices operating in the broad range of the electromagnetic spectrum covering infrared to terahertz wavelengths. However, the epitaxial growth of these heterostructures at a thickness of a few microns has been a challenging task due the lattice...

Recent development on Ge 1−x Sn x nanowires with high Sn content, beyond its solid solubility limit, makes them attractive for all group-IV Si-integrated infrared photonics at the nanoscale. Herein, we report a chemical vapor deposition-grown high Sn-content Ge–Ge 0.92 Sn 0.08 core–shell based single nanowire photodetector operating at the optical...

Despite the recent success of GeSn infrared lasers, the high lasing threshold currently limits their integration into practical applications. While structural defects in epitaxial GeSn layers have been identified as one of the major bottlenecks towards low-threshold GeSn lasers, the effect of defects on the lasing threshold has not been well studie...

A theoretical framework incorporating atomic-level interfacial details is derived to include the electronic structure of buried interfaces and describe the behavior of charge carriers in heterostructures in the presence of finite interfacial broadening. Applying this model to ultrathin heteroepitaxial (SiGe)m/(Si)m superlattices predicts the existe...

The prospect of GeSn semiconductors for silicon-integrated infrared optoelectronics brings new challenges related to the metastability of this class of materials. As a matter of fact, maintaining a reduced thermal budget throughout all processing steps of GeSn devices is essential to avoid possible material degradation. This constraint is exacerbat...

The monolithic integration of extended short-wave infrared (e-SWIR) photodetectors (PDs) on silicon is highly sought-after to implement manufacturable, cost-effective sensing and imaging technologies. With this perspective, GeSn PIN PDs have been the subject of extensive investigations because of their bandgap tunability and silicon compatibility....

Semiconductor nanowires have emerged as versatile components in superconducting hybrid devices for Majorana physics and quantum computing. The transport properties of nanowires can be tuned either by field effect or doping. We investigated a series of InAs nanowires the conductivity of which has been modified by n-type doping using tellurium. In ad...

Advances in quantum technology may come from the discovery of new materials systems that improve the performance or allow for new functionality in electronic devices. Lead telluride (PbTe) is a member of the group IV-VI materials family that has significant untapped potential for exploration. Due to its high electron mobility, strong spin-orbit cou...

Indium antimonide (InSb) nanowires are used as building blocks for quantum devices because of their unique properties, that is, strong spin‐orbit interaction and large Landé g‐factor. Integrating InSb nanowires with other materials could potentially unfold novel devices with distinctive functionality. A prominent example is the combination of InSb...

Recent development on Ge$_{1-x}$Sn$_x$ nanowires with high Sn content, beyond its solid solubility limit, make them attractive for all group-IV Si-integrated infrared photonics at nanoscale. Herein, we report a chemical vapour deposition-grown high Sn-content Ge-Ge$_{0.92}$Sn$_{0.08}$ core-shell based single nanowire photodetector operating at the...

A method based on complementary transmission and reflection measurements is developed to determine the complex refractive index of an ultrathin layer, despite no knowledge of the substrate's absorption loss. Such a technique avoids error introduced by conventional methods in which the extinction coefficient of the substrate is extracted from a diff...

We report optically pumped low-threshold lasing in GeSnOI microdisk lasers with reduced defect density. The measured lasing threshold of 17 kW/cm ² was 10 times lower than that of the control sample containing highly defective interfaces.

Monolithic all-group IV GeSn PIN detector and emitting devices were fabricated and their bandwidth was measured. The obtained high bandwidth PDs were utilized in time resolved spectroscopy in the picosecond range.

Complementary reflection and transmission measurements are used in conjunction with a Fresnel-based modeling approach to determine the refractive index and extinction coefficient of thin film layers, despite no prior knowledge of the substrate’s extinction coefficient.

The quiet quantum environment of holes in solid-state devices has been at the core of increasingly reliable architectures for quantum processors and memories.1-6 However, due to the lack of scalable materials to properly tailor the valence band character and its energy offsets, the precise engineering of light-hole (LH) states remains a serious obs...

Electron spins in Si/SiGe quantum wells suffer from nearly degenerate conduction band valleys, which compete with the spin degree of freedom in the formation of qubits. Despite attempts to enhance the valley energy splitting deterministically, by engineering a sharp interface, valley splitting fluctuations remain a serious problem for qubit uniform...

GeSn alloys are promising candidates for complementary metal‐oxide‐semiconductor‐compatible, tunable lasers. Relaxation of residual compressive strain in epitaxial GeSn has recently shown promise in improving the lasing performance. However, the suspended device configuration that is thus far introduced to relax the strain is destined to limit heat...

GeSn alloys have been regarded as a potential lasing material for a complementary metal–oxide–semiconductor-compatible light source. Despite their remarkable progress, all GeSn lasers reported to date have large device footprints and active areas, which prevent the realization of densely integrated on-chip lasers operating at low power consumption....

The prospect of GeSn semiconductors for silicon-integrated infrared optoelectronics brings new challenges related to the metastability of this class of materials. As a matter of fact, maintaining a reduced thermal budget throughout all processing steps of GeSn devices is essential to avoid possible material degradation. This constraint is exacerbat...

Group IV Ge1-xSnx semiconductors hold the premise of enabling broadband silicon-integrated infrared optoelectronics due to their tunable bandgap energy and directness. Herein, we exploit these attributes along with the enhanced lattice strain relaxation in Ge/Ge0.92Sn0.08 core-shell nanowire heterostructures to implement highly responsive, room-tem...

Indium antimonide (InSb) nanowires are used as building blocks for quantum devices because of their unique properties, i.e., strong spin-orbit interaction and large Land\'e g-factor. Integrating InSb nanowires with other materials could potentially unfold novel devices with distinctive functionality. A prominent example is the combination of InSb n...

The availability of high-frequency pulsed emitters in the $2-2.5\,\mu$m wavelength range paved the way for a wealth of new applications in ultrafast spectroscopy, free-space and fiber-optical communications, surveillance and recognition, artificial intelligence, and medical imaging. However, developing these emerging technologies and their large-sc...

Advances in quantum technology may come from the discovery of new materials systems that improve the performance or allow for new functionality in electronic devices. Lead telluride (PbTe) is a member of the group IV-VI materials family that has significant untapped potential for exploration. Due to its high electron mobility, strong spin-orbit cou...

Semiconductor nanowires have emerged as versatile components in superconducting hybrid devices for Majorana physics and quantum computing. The transport properties of nanowires can be tuned either by field-effect or doping. We investigated a series of InAs nanowires which conductivity has been modified by n-type doping using tellurium. In addition...

Phonon surface scattering has been at the core of heat transport engineering in nanoscale devices. Herein, we demonstrate that this phonon pathway can be the sole mechanism only below a critical, size-dependent temperature. Above this temperature, the lattice phonon scattering coexists along with surface effects. By tailoring the mass disorder at t...

GeSn alloys have been regarded as a potential lasing material for a complementary metal-oxide-semiconductor (CMOS)-compatible light source. Despite their remarkable progress, all GeSn lasers reported to date have large device footprints and active areas, which prevent the realization of densely integrated on-chip lasers operating at low power consu...

Interlayer twisting in two-dimensional (2D) van der Waals (vdW) heterostructures often leads to a periodic moiré pattern which is a superlattice structure on top of the original atomic lattice of the 2D layers. The formation of a moiré superlattice can be accompanied by a significant structural reconstruction and ultra-flat electronic bands. The mo...

This work unravels the atomic details of the interaction of solute atoms with nanoscale crystalline defects. The complexity of this phenomenon is elucidated through detailed atom probe tomographic investigations on epitaxially-strained, compositionally metastable, semiconductor alloys. Subtle variations are uncovered in the concentration and distri...

GeSn alloys are promising candidates for complementary metal-oxide-semiconductor (CMOS)-compatible, tunable lasers. Relaxation of residual compressive strain in epitaxial GeSn has recently shown promise in improving the lasing performance. However, the suspended device configuration that has thus far been introduced to relax the strain is destined...

Pnictogens (P, As, Sb, Bi) emerged as a new class of elemental 2D materials displaying a wide range of electronic and topological properties. With their ns2 np3 valence electronic configuration and sp ³ hybridization, group VA elements are the only elemental group which forms vdW and quasi-vdW structures throughout the entire group, thus providing...

(Si)GeSn semiconductors are finally coming of age after a long gestation period. The demonstration of device-quality epi-layers and quantum-engineered heterostructures has meant that tunable all-group IV Si-integrated infrared photonics is now a real possibility. Notwithstanding the recent exciting developments in (Si)GeSn materials and devices, th...