The polar nature of the wurtzite crystalline structure GaN and ZnO results in existence a spontaneous electric polarization within these materials their associated alloys (Ga,Al,In)N (Zn,Mg,Cd)O. polarity has also important consequences on stability different crystallographic surfaces, this becomes especially when considering epitaxial growth. Furthermore, internal fields may adversely affect properties optoelectronic devices but is used as potential advantage for advanced electronic...

In the context of advanced photonics or photovoltaics, monolithic integration high-quality III-V materials as near possible to Si substrate is great interest. Here, authors experimentally and theoretically clarify III-V/Si crystal growth processes. Monodomain 3D islands are observed at early stages AlSb, AlN, GaP epitaxy on Si, independently misfit. It shown that complete wetting cannot be achieved in most systems. Surface/interface contributions free energy variations found prominent over...

Abstract Ultrawide bandgap (UWBG) semiconductors offer new possibilities to develop power electronics. High voltage operation for the off‐state as well high temperature stability of devices in on‐state are required. More than AlGaN/GaN heterostructures, AlGaN/AlGaN heterostructures promising candidates meet these criteria. Furthermore, possibility choose Al molar fraction AlGaN paves way more tunable heterostructures. In this study, electronic transport properties channel grown on silicon...

The vertical bulk (drain-bulk) current (Idb) properties of analogous AlGaN/GaN hetero-structures molecular beam epitaxially grown on silicon, sapphire, and free-standing GaN (FS-GaN) have been evaluated in this paper. experimental Idb (25–300 °C) well reproduced with physical models based a combination Poole-Frenkel (trap assisted) hopping (resistive) conduction mechanisms. thermal activation energies (Ea), the (soft or destructive) breakdown voltage (VB), effect inverting drain-bulk...

This letter reports on the demonstration of microwave power performance at 40 GHz AlGaN/GaN high-electron mobility transistor grown silicon (111) substrate by molecular beam epitaxy. A maximum dc current density 1.1 A· mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> and a peak extrinsic transconductance 374 mS · are obtained for 75-nm gate length device. At VDS = 25 V, continuous-wave output 2.7 W is achieved associated with 12.5%...

We present a series of microdisk lasers realized within the same GaN-on-Si photonic platform scheme, and operating at room temperature under pulsed optical pumping over broad spectral range extending λ = 275 nm–470 nm. The III-nitride microdisks embed either binary GaN/AlN multiple quantum wells (MQWs) for UV operation, or ternary InGaN/GaN MQWs violet blue operation. This demonstrates versatility this nitride-on-silicon platform, realization on efficient active layers lasing action 200 nm...

The main interest of group-III-nitride nanophotonic circuits is the integration active structures and laser sources. A photonic platform microdisk lasers integrated on silicon emitting in blue spectral range demonstrated. microdisks are side-coupled to suspended bus waveguides, coupled emission guided outcoupled free space using grating couplers. small gap size less than 100 nm between disk waveguide required for optimal evanescent coupling. To avoid reabsorption waveguide, quantum wells...

In this paper, we propose to optimize Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.29</sub> Ga xmlns:xlink="http://www.w3.org/1999/xlink">0.71</sub> N/GaN heterostructures on silicon substrate obtain high electron mobility transistors featuring high-power/frequency performances. The polarization electric fields are engineered by varying the layer thicknesses of cap and barrier, changing type buffer (GaN or AlGaN). aim paper is find best...

We demonstrate low-loss GaN/AlGaN planar waveguides grown by molecular beam epitaxy on sapphire substrates. By using a proper AlGaN cladding layer and reducing surface roughness we reach <1dB/cm propagation losses at 633nm. These low allow an efficient second harmonic generation modal phase matching between TM0 pump 1260nm TM2 630nm. A maximal power conversion of 2% is realized with efficiency 0.15%·W-1cm-2. provide modelling that demonstrates broadband features platform showing wavelengths...

AlN-on-Si can be considered as a model system for heteroepitaxial growth of highly mismatched materials. Indeed, AlN and Si drastically differ in terms chemistry, crystalline structure, lattice parameters. In this paper, we present transmission electron microscopy grazing incidence X-ray diffraction study the microstructure layers epitaxially grown on (111) by molecular beam epitaxy. The large interfacial energy due to dissimilarities between results 3D Volmer-Weber mode with nucleation...

We retrieve the complex optical index of single-walled carbon nanotube (CNT) films in 0.6-800 μm spectral range. Results are obtained from a complete set measurements, reflection and transmission, free-standing CNT using time domain spectroscopy terahertz (THz) Fourier transform infrared (IR) visible-IR. Based on Drude-Lorentz model, our results reveal global metallic behavior IR, confirm their high THz

AlN‐based HEMTs grown on silicon by ammonia‐assisted molecular beam epitaxy (NH 3 ‐MBE) are demonstrated and studied. As shown photoluminescence, the very thin GaN channel (35–55 nm‐thick) is compressively strained 250 nm‐thick relaxed AlN buffer layer substrate. The structure then completed an 8 barrier 2 cap. Despite ultrathin total epilayer (only ≈300 nm‐thick), a high 2DEG density (≈2.7 × 10 13 cm −2 ) measured Hall effect. Room temperature mobility values, as 636 V −1 s , measured. They...

Nanophotonic circuits using group III-nitrides on silicon are still lacking one key component: efficient electrical injection. In this paper we demonstrate an injection scheme a metal microbridge contact in thin III-nitride mushroom-type microrings that is compatible with integrated nanophotonic the goal of achieving electrically injected lasing. Using central buried n-contact to bypass insulating buffer layers, able underetch microring, which essential for maintaining vertical confinement...

We investigate the demonstration and quantification of strong coupling between excitons guided photons in a GaN slab waveguide. The dispersions waveguide polaritons are measured from T=6~K to 300~K through gratings. They carefully analyzed within four models based on different assumptions, order assess regime. prove that strongly coupled at all investigated temperatures, with small $(11 \%)$ dependence temperature. However values Rabi splitting vary among models: "coupled oscillator" model...

We experimentally demonstrate the difference between a ridge polariton laser, and conventional edge-emitting laser operating under electron-hole population inversion. The horizontal cavities are 20 -- 60 $\mu$m long GaN etched structures with vertical Bragg reflectors. investigate threshold optical pumping assess quantitatively effect of varying optically-pumped length. is achieved for an exciton reservoir length just 15% cavity length, which would not be possible in inversion-less...

On-chip microlaser sources in the blue constitute an important building block for complex integrated photonic circuits on silicon. We have developed operating spectral range based microdisks and bus waveguides III-nitride report interplay between microdisk-waveguide coupling its optical properties. observe critical phase matching, i.e. most efficient energy transfer scheme, very short gap sizes thin (g = 45 nm w 170 nm) spontaneous emission regime. Whispering gallery mode lasing is...

We demonstrate intersubband polaritons in the short-infrared wavelength range (λ &amp;lt; 3 μm) relying on GaN/AlN semiconductor system. The demonstration is given for an transition centered at λ = 3.07 μm (E 403 meV). polaritonic dispersion measured room temperature: a Rabi energy of 53 meV (i.e., minimum splitting 106 meV), which represents 13.1% bare transition, demonstrated. A metal-insulator-metal resonator architecture employed, proves to be efficient even these short wavelengths.

Abstract We report on the study of AlGaN/GaN high electron mobility transistors (HEMTs) incorporating an InGaN back‐barrier grown by ammonia‐assisted molecular beam epitaxy (NH 3 ‐MBE). The structural characterizations confirm good crystalline quality heterostructure and pseudomorphic growth InGaN. This is also verified Hall effect about 2130 cm 2 V −1 s . associated two‐dimensional gas carrier concentration in range 8 × 10 12 −2 for heterostructures GaN:Fe‐on‐sapphire templates. Normal DC...

Submicrometer‐thick AlGaN/GaN high‐electron‐mobility transistor (HEMT) epilayers grown on silicon substrate with a state‐of‐the art vertical buffer breakdown field as high 6 MV cm −1 enabling voltage of 250 V for short gate‐to‐drain distances despite such thin structure are reported. HEMTs gate length 100 nm exhibit good DC characteristics low drain‐induced barrier, going mV DS 30 V. Breakdown voltages each epilayer from the decomposed heterostructure reveals that outstanding strength is...

The rapidly increasing power demand, downsizing of electronics and material specific limitation silicon has led to development AlGaN/GaN heterostructures. Commercial GaN devices are best available for radio frequency (RF) high voltage switching applications. Emerging AlxGa1-xN channel based heterostructures promising enhance the limits next generation devices. In this work, we report on study electrical performance AlGaN HEMTs-on-Silicon using various Al content. fabricated exhibited...

The performance of gallium nitride transistors is still limited by technological problems often related to defects and traps. In this work, virgin AlGaN/AlN/GaN HEMTs exhibiting an anomalous DC behavior accompanied frequency dispersion in the microwave range, both transconductance output conductance, are analyzed. This response, which mitigated high-bias conditions, attributed presence traps volume GaN channel source drain contacts. A simple equivalent circuit model proposed replicate...

III-nitride-on-silicon L3 photonic crystal cavities with resonances down to 315 nm and quality factors (Q) up 1085 at 337 have been demonstrated. The reduction of the factor decreasing wavelength is investigated. Besides quantum well absorption below 340 nm, a noteworthy contribution attributed residual present in thin AlN layers grown on silicon, as measured by spectroscopic ellipsometry. This ultimately limits Q around 2000 300 when no active layer present.

Many high-field/attosecond and ultrafast electron diffraction/microscopy experiments on condensed matter require samples in the form of free-standing membranes with nanometer thickness. Here, we report measurement laser-induced damage threshold 11 different nanometer-thin metallic, semiconducting, insulating materials for 1-ps, 1030-nm laser pulses at 50 kHz repetition rate. We find a that is very similar to each corresponding bulk material. The measurements also reveal band gap dependence...

Abstract We report the realization and optical study of nitride photonic resonators dedicated to blue UV spectral range. Microdisks crystal (PC) cavities are investigated containing GaN/AlN quantum dots (QDs) embedded in an AlN waveguide. The PC fabricated through conformal growth nitrides on a patterned Si substrate, present delocalized confined cavity modes their microphotoluminescence spectra, that compared simulations. A large quality factor 1800 is reached for modified L3 cavity. In...