We demonstrate tunable Schottky barrier height and record photo-responsivity in a new-concept device made of single-layer CVD graphene transferred onto matrix nanotips patterned on n-type Si wafer. The original layout, where nano-sized graphene/Si heterojunctions alternate to areas exposed the electric field substrate, which acts both as diode cathode transistor gate, results two-terminal barristor with single-bias control barrier. nanotip patterning favors light absorption, enhancement at...

Abstract The short‐wave infrared (SWIR) is an underexploited portion of the electromagnetic spectrum in metasurface‐based nanophotonics despite its strategic importance sensing and imaging applications. This mainly attributed to lack material systems tailor light–matter interactions this range. Herein, limitation addressed all‐dielectric silicon‐integrated metasurface enabling polarization‐induced Fano resonance control at SWIR frequencies demonstrated. platform consists a 2D Si/Ge 0.9 Sn...

Dislocation networks are one of the most principle sources deteriorating performances devices based on lattice-mismatched heteroepitaxial systems. We demonstrate here a technique enabling fully coherent germanium (Ge) islands selectively grown nanotip-patterned Si(001) substrates. The silicon (Si)-tip-patterned substrate, fabricated by complementary metal oxide semiconductor compatible nanotechnology, features ∼50-nm-wide Si areas emerging from SiO2 matrix and arranged in an ordered lattice....

Abstract The integration of dislocation-free Ge nano-islands was realized via selective molecular beam epitaxy on Si nano-tip patterned substrates. Si-tip wafers feature a rectangular array nanometer sized tips with (001) facet exposed among SiO 2 matrix. These were fabricated by complementary metal-oxide-semiconductor (CMOS) compatible nanotechnology. Calculations based nucleation theory predict that the growth occurs close to thermodynamic equilibrium, where condensation adatoms is...

We report the observation of field emission from InP nanocrystals epitaxially grown on an array p-Si nanotips. prove that can be enhanced by covering with graphene. The measurements are performed inside a scanning electron microscope chamber nano-controlled W-thread used as anode. analyze Fowler-Nordheim theory and find enhancement factor increases monotonically spacing between anode cathode. also show InP/p-Si junction has rectifying behavior, while graphene creates ohmic contact....

The threading dislocation density (TDD) in plastically relaxed Ge/Si(001) heteroepitaxial films is commonly observed to decrease progressively with their thickness due mutual annihilation. However, there exists a saturation limit, known as the geometrical beyond which further of TDD Ge film hindered. Here, we show that such limit can be overcome SiGe/Ge/Si heterostructures thanks beneficial role second interface. Indeed, ${\mathrm{Si}}_{0.06}{\mathrm{Ge}}_{0.94}/\mathrm{Ge}/\mathrm{Si}(001)$...

Indium phosphide (InP) nanoislands are grown on pre-patterned Silicon (001) nanotip substrate using gas-source molecular-beam epitaxy via nanoheteroepitaxy approach. The study explores the critical role of growth temperature in achieving selectivity, governed by diffusion length. Our reveals that temperatures about 480 °C and lower, lead to parasitic growth, while 540 with an indium rate 0.7 Å.s−1 phosphine flux 4 sccm inhibit selective growth. establishment optimal window for InP is...

The epitaxial integration of highly heterogeneous material systems with silicon (Si) is a central topic in (opto-)electronics owing to device applications. InP could open new avenues for the realization novel devices such as high-mobility transistors next-generation CMOS or efficient lasers Si photonics circuitry. However, InP/Si heteroepitaxy challenging due lattice (∼8%), thermal expansion mismatch (∼84%), and different symmetries. Here, we demonstrate growth nanocrystals showing high...

Quantum cascade lasers are finicky, in terms of the structural quality active region, especially for strain-mismatched heterostructures like Ge/Si-Ge quantum wells. Accurate control electron-state coupling between well and barriers laser's different stages is crucial. This study shows how to produce high-quality asymmetric coupled $n$-type multiple wells carefully resonant tunneling through thicknesses, thus interwell wave-function hybridization. The set robust material parameters provided...

Abstract We investigate the temperature dependence of Ge Raman mode strain–phonon coefficient in Ge/Si heteroepitaxial layers. By analyzing temperature‐dependent evolution both Ge─Ge line and lattice strain, we obtain a linear as function temperature. Our findings provide an efficient method for capturing strain relaxation mechanism systems. Furthermore, show that rather large variability reported literature values might be due to local heating sample excitation laser used μ‐Raman experiments.

Gallium phosphide (GaP) is a III–V semiconductor with remarkable optoelectronic properties, and it has almost the same lattice constant as silicon (Si). However, to date, monolithic large-scale integration of GaP devices remains challenging. In this study, we present nanoheteroepitaxy approach using gas-source molecular-beam epitaxy for selective growth islands on Si nanotips, which were fabricated complementary metal–oxide (CMOS) technology 200 mm n-type Si(001) wafer. Our results show that...

To develop a III/V wide bandgap collector concept for future SiGe heterobipolar transistor performance increase, heterostructure growth study of GaP on pseudomorphic 4° off-oriented Si0.8Ge0.2/Si(001) substrates was performed. For GaP/Si0.8Ge0.2/Si(001) growth, critical thickness Si and maximum thermal budget deposition were evaluated. A detailed structure defect characterization by x-ray diffraction, atomic force microscopy, transmission electron microscopy is reported single crystalline...

We present the nanoheteroepitaxial growth of gallium arsenide (GaAs) on nano-patterned silicon (Si) (001) substrates fabricated using a CMOS technology compatible process. The selective GaAs nano-crystals (NCs) was achieved at 570 °C by MOVPE. A detailed structure and defect characterization study grown nano-heterostructures performed scanning transmission electron microscopy, x-ray diffraction, micro-Raman, micro-photoluminescence (μ-PL) spectroscopy. results show single-crystalline, nearly...

Nano-heteroepitaxial growth of GaAs on Si(001) by metal organic vapor phase epitaxy was investigated to study emerging materials phenomena the nano-scale III–V/Si interaction. Arrays Si nano-tips (NTs) embedded in a SiO2 matrix were used as substrates. The NTs had top openings 50–90 nm serving seeds for selective nano-crystals (NCs). structural and morphological properties high resolution scanning electron microscopy, atomic force backscatter diffraction, x-ray transmission microscopy. led...

In this paper we deposit structures comprising a stack of 10 periods made 15-nm-thick Ge multiple quantum wells (MQWs) enclosed in Si0.2Ge0.8 barrier on SiGe virtual substrates (VSs) featuring different content the 85%–100% range to investigate influence heteroepitaxial strain and growth. With increasing concentration VS, growth rate MQWs increases. Si incorporation into layer also becomes slightly higher. However, almost no is observed for MQWs. We argue that increased tensile promotes...

In this letter, we explore in detail the potential of nanoheteroepitaxy to controllably fabricate high quality GeSn nano-structures and further improve crystallinity alloys directly grown on Si(001). The was by molecular beam epitaxy at relatively temperatures up 750 °C pre-patterned Si nano-pillars embedded a SiO2 matrix. best compromise between selective growth homogenous Sn incorporation 1.4% achieved temperature 600 °C. X-ray diffraction measurements confirmed that our approach results...

Highly polar materials are usually preferred over weakly ones to study strong electron-phonon interactions and its fascinating properties. Here, we report on the achievement of simultaneous confinement charge carriers phonons at vicinity a 2D vertical homovalent singularity (antiphase boundary, APB) in an (In,Ga)P/SiGe/Si sample. The impact interaction photoluminescence processes is then clarified by combining transmission electron microscopy, X-ray diffraction, ab initio calculations, Raman...

Temperature dependence of vibrational modes in semiconductors depends on lattice thermal expansion and anharmonic phonon-phonon scattering. Evaluating the two contributions from experimental data is not straightforward, especially for epitaxial layers that present mechanical deformation anisotropic expansion. In this work, a temperature-dependent Raman study Ge Ge$_{1-x}$Sn$_{x}$ presented. A model introduced mode energy shift as function temperature, comprising strained corrections. With...

In this work, we demonstrate the growth of Ge crystals and suspended continuous layers on Si(001) substrates deeply patterned in high aspect-ratio pillars. The material deposition was carried out a commercial reduced-pressure chemical vapor reactor, thus extending "vertical-heteroepitaxy" technique developed by using peculiar low-energy plasma-enhanced to widely available epitaxial tools. process thoroughly analyzed, from formation small initial seeds final coalescence into layer, means...

Germanium (Ge) nanowires (NWs) were grown in-plane on nano-structured Si(001)/SiO2 substrates by molecular beam epitaxy using gold (Au) as the solvent. The site-selective NW growth was enabled a rectangular array of droplets silicon (Si) tips with an Au nuclei density below 0.25 µm−2 surrounding oxide (SiO2). initial Ge NWs starting from Si–Au SixGe1−x nucleation ternary alloy is discussed thermodynamic point view. elongation occurred within 〈110〉 directions substrate and mainly bounded two...

We present the morphological evolution obtained during annealing of Ge strips grown on Si ridges as a prototypical process for 3D device architectures and nanophotonic applications. In particular, transition occurring from Ge/Si nanostrips to nanoislands is illustrated. The combined effect performing at different temperatures varying lateral size ridge underlying addressed by means synergistic experimental theoretical analysis. Indeed, three-dimensional phase-field simulations surface...

We report a detailed structure and defect characterization study on gallium phosphide (GaP) layers integrated silicon (Si) (001) via silicon-germanium (SiGe) buffer layers. The presented approach uses an almost fully relaxed SiGe heterostructure of only 400 nm thickness whose in-plane lattice constant is matched to GaP—not at room but GaP deposition temperature. Single crystalline, pseudomorphic 270 thick successfully grown by metalorganic chemical vapour Si0.85Ge0.15/Si(001) heterosystem,...

Crystal defects, present in ~100 nm GaAs nanocrystals grown by metal organic vapour phase epitaxy on top of (0 0 1)-oriented Si nanotips (with a tip opening 50–90 nm), have been studied means high-resolution aberration-corrected high-angle annular dark-field scanning transmission electron microscopy. The role 60° perfect, 30° and 90° Shockley partial misfit dislocations (MDs) the plastic strain relaxation is discussed. Formation conditions stair-rod coherent twin boundaries are explained....

We investigate the distribution of Sn in GeSn nano-heteroepitaxial clusters deposited at temperatures well exceeding eutectic temperature system. The 600 °C molecular beam epitaxy on Si-patterned substrates results selective growth nano-clusters having a 1.4 ± 0.5 at% content. These feature droplets their faceted surfaces. subsequent deposition thin Ge cap layer induced incorporation atoms segregated surface wetting nano-dots with 8 Sn. presence this is associated relatively strong...