A droop-free nitride light-emitting diode (LED) with the capacity to operate beyond "green gap" has been a subject of intense scientific and engineering interest. While several properties nanowires on silicon make them promising for use in LED development, high aspect ratio individual their laterally discontinuous features limit phonon transport device performance. Here, we report monolithic integration metal heat-sink InGaN/GaN quantum-disks-in-nanowire LEDs emitting at ∼710 nm. The...

An organic passivation process for nitride nanowires was first proposed to reduce Shockley–Read–Hall non-radiative recombination of nanowire light emitting diodes.

High-quality nitride materials grown on scalable and low-cost metallic substrates are considerably attractive for high-power light-emitters. We demonstrate here, the first time, red (705 nm) InGaN/GaN quantum-disks (Qdisks)-in-nanowire light-emitting diodes (LEDs) self-assembled directly metal-substrates. The LEDs exhibited a low turn-on voltage of ∼2 V without efficiency droop up to injection current 500 mA (1.6 kA/cm(2)) at ∼5 V. This is achieved through direct growth optimization...

The photoinduced entropy of InGaN/GaN p-i-n nanowires was investigated using temperature-dependent (6–290 K) photoluminescence. We also analyzed the photocarrier dynamics in InGaN active regions time-resolved An increasing trend amount generated system above 250 K observed, while we observed an oscillatory below that stabilizes between 200 and K. Strong exciton localization indium-rich clusters, carrier trapping by surface defect states, thermodynamic effects were examined related to...

Magnetron sputter epitaxy (MSE) offers several advantages compared to alternative GaN growth methods, including mature sputtering technology, the possibility for very large area deposition, and low-temperature of high-quality electronic-grade GaN. In this article, we review basics reactive MSE using a liquid Ga target. Various target biasing schemes are discussed, direct current (DC), radio frequency (RF), pulsed DC, high-power impulse magnetron (HiPIMS). Examples given MSE-grown thin films...

In this paper, a GNU Radio based software-defined FMCW (Frequency Modulated - Continuous Wave) radar is studied for weather surveillance application. The that has been gaining popularity due to the use of solid state microwave amplifier generate signal source proposed design since current usually using pulse-radar type needs high power in pulse generation and cost deployment. addition, by radar, therefore designed can be implemented configured at reduced complexity. prototype both open...

High-quality nitride nanowires on large-area layered transition metal dichalcogenides are first reported, which yielded light-emitting diodes (LEDs) with superior performance.

In this paper, we describe ultraviolet-A (UV-A) light-emitting diodes (LEDs) emitting at 325 nm based on a highly uniform structure of quantum-confined AlGaN quantum-disk nanowires (NWs).By incorporating 20 TaN interlayer between Ti preorienting layer and the silicon substrate, eliminated potential barrier for carrier injection phonon transport, inhibited formation interfacial silicide that led to device failure.Compared previous reports metal achieved 16 × reduction in root-mean-square...

There have been recent research advances in AlGaN-based self-assembled nanowires (NWs) as building blocks for ultraviolet (UV) optoelectronics grown by plasma-assisted molecular beam epitaxy. We review the basic growth kinetics on various foundry-compatible-metal/silicon-based substrates and epistructure design UV devices. highlight use of diffusion-barrier-metal thin film silicon substrate a solution to enhance device performance. NWs offer opportunity mitigate detrimental quantum-confined...

An urgent challenge for the lighting research community is lack of efficient optical devices emitting in between 500 and 600 nm, resulting "green-yellow gap". In particular, true green (∼555 nm) yellow (∼590 nm), along with blue red, constitute four technologically important colors. The III-nitride material system, being most promising choice platform to bridge this gap, still suffers from high dislocation density poor crystal quality realizing high-power, devices. Particularly, polarization...

Group-III nitride nano-dimensional materials with noncentrosymmetric crystal structure offer an exciting area of piezotronics for energy conversion applications. We experimentally report the piezotronic and piezo-phototronic effects n-InGaN nanowires (NWs) having emission wavelength in visible region (≈510 nm). The n-type InGaN NWs, exhibiting high structural optical quality, were grown by plasma-assisted molecular beam epitaxy (PAMBE) on Ti/TaN/Si substrates to facilitate direct bottom...

Consumer electronics have increasingly relied on ultra-thin glass screen due to its transparency, scalability, and cost. In particular, display technology relies integrating light-emitting diodes with panel as a source for backlighting. this study, we undertook the challenge of light emitters onto amorphous quartz by demonstrating direct growth fabrication III-nitride nanowire-based diode. The proof-of-concept device exhibits low turn-on voltage 2.6 V, an substrate. We achieved ~ 40%...

We study the impact of quantum-confined stark effect (QCSE) on bias dependent micro-photoluminescence emission quantum disk (Q-disk) based nanowires light emitting diodes (NWs-LED) exhibiting amber colored emission. The NWs are found to be nitrogen polar (N-polar) verified using KOH wet chemical etching and valence band spectrum analysis high-resolution X-ray photoelectron spectroscopy. crystal structure quality were investigated by high-angle annular dark field - scanning transmission...

Group-III-nitride laser diode (LD)-based solid-state lighting device has been demonstrated to be droop-free compared light-emitting diodes (LEDs), and highly energy-efficient that of the traditional incandescent fluorescent white light systems. The YAG:Ce3+ phosphor used in LD-based lighting, however, is associated with rapid degradation issue. An alternate phosphor/LD architecture, which capable sustaining high temperature, power density, while still intensity- bandwidth-tunable for...

Growing III-nitride nanowires on 2D materials is advantageous, as it effectively decouples the underlying growth substrate from properties of nanowires. As a relatively new family materials, MXenes are promising candidates nanowire nucleation layers capable providing simultaneous transparency and conductivity. In this work, we demonstrate direct epitaxial GaN Ti3C2 MXene films. The films consist nanoflakes spray coated onto an amorphous silica substrate. We observed relationship between due...

The dislocation free InxAl1-xN nanowires (NWs) are grown on Si(111) by nitrogen plasma assisted molecular beam epitaxy in the temperature regime of 490 °C–610 °C yielding In composition ranges over 0.50 ≤ x 0.17. We study optical properties these NWs spectroscopic ellipsometry (SE), photoluminescence, and Raman spectroscopies since they possesses minimal strain with reduced defects comparative to planar films. bandgap measurements demonstrated SE where absorption edges NW samples evaluated...

In this paper, c-plane stepped-and graded-InGaN/GaN multiple quantum wells (MQWs) are grown using plasma assisted molecular beam epitaxy (PAMBE) by in situ surface stoichiometry monitoring (i-SSM).Such a technique considerably reduces the strain build-up due to indium clustering within and across graded-MQWs; especially for QW closer top which results mitigation of quantum-confined Stark effect (QCSE).This is validated reduced power dependent photoluminescence blueshift 10 meV graded-MQWs as...

The optimization of magnetron sputter epitaxy (MSE) for the high-volume production high-quality GaN films is increasingly important. This study concerns influence key MSE process parameters - including partial pressure gas, target-to-substrate distance (TSD), and growth temperature (TG) synthesis thin using a liquid Ga target. It observed that effective Ga/N ratio on substrate surface determines film's behavior affects material's composition luminescence properties. A lower Ar/N2...

We report on development of 1130nm oxide VCSELs based InGaAs/GaAs active material system and AlGaAs distributed Bragg reflectors (DBRs). To our knowledge, this is the first multijunction at wavelength.

The diode junction temperature (Tj) of light emitting devices is a key parameter affecting the efficiency, output power, and reliability. Herein, we present experimental measurements Tj on ultraviolet (UV) AlGaN nanowire (NW) diodes (LEDs), grown thin metal-film silicon substrate using forward voltage electroluminescence peak-shift methods. forward-voltage vs curves show coefficient dVF/dT values −6.3 mV/°C −5.2 mV/°C, respectively. significantly smaller ∼61 °C measured for sample metal...

Group-III nitride-based ultraviolet (UV) quantum-disks (Qdisks) nanowires (NWs) light-emitting diodes grown on silicon substrates offer a scalable, environment-friendly, compact, and low-cost solution for numerous applications in solid-state lighting, spectroscopy, biomedical. However, the internal quantum efficiency, injection extraction efficiency need to be further improved. The focus of this paper encompasses investigations based structural optimization, device simulation, reliability....

In this work, we demonstrated the direct growth of GaN nanowires on indium tin oxide (ITO)-coated fused silica substrate. The were grown catalyst-free using plasma-assisted molecular beam epitaxy (PA-MBE). effect condition morphology and quality is systematically investigated. Structural characterization indicates that grow in (0001) direction directly top ITO layer perpendicular to substrate plane. Optical shows yellow luminescence absent from nanowire's photoluminescence response,...

White light based on blue laser – YAG: Ce³⁺ phosphor has the advantage of implementing solid-state lighting and optical wireless communications combined-functionalities in a single lamp. However, was found to disrupt melatonin production, therefore human circadian rhythm general; while yellow is susceptible degradation by irradiation also lack tunability color rendering index (CRI). In this investigation, using violet laser, which 50% less impact response, as compared light, an...

We report on the study and characterization of nanoclusters-related recombination centers within quantum-disks-in-nanowires heterostructure by utilizing microphotoluminescence (μ-PL) cathodoluminescence scanning transmission electron microscopy (CL-STEM). μ-PL measurement shows that center exhibits different temperature-dependent characteristics compared with surrounding InGaN quantum-disks-related center. CL-STEM measurements reveal these mainly arise from irregularities quantum disks, a...

Selective-area grown, catalyst-free GaN nanorod (NR) arrays grown on Si substrates have been realized using liquid-target reactive magnetron sputter epitaxy (MSE). Focused ion beam lithography (FIBL) was applied to pattern with TiNx masks. A liquid Ga target sputtered in a mixture gas of Ar and N2, ranging the N2 partial pressure (PN₂) ratio from 100% 50%. The growth NRs shows strong correlation PN₂ selectivity, coalescence, rate both radial axial directions. formed inside nanoholes...