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Fully functional thin-film blue LED was fabricated by novel means of (1) performing epitaxial growth of a single crystalline InGaN/GaN heterostructure on a recycled graphene/SiC substrate (2) followed by release and transfer of the heterostructure.
GaN emitters have historically been of hexagonal phase due to natural crystallization. Here we introduce a cubic phase GaN emitter technology that is polarization-free via cointegration on cheap and scalable CMOS-compatible Si(100) substrate.
We report on the monolithic integration of RGB InGaN dot-in-a-wire LEDs on a single chip. The correlated color temperature can be continuously varied in the range of 1900K to 6800K, while maintaining excellent color rendering index capability (CRI>90). Moreover, submicron scale RGB pixels were demonstrated.
The main objective of the Delphi4LED project (funded by the Ecsel European joint undertaking) is to develop a standardized method to create multidomain LED based design and simulation flow for the solid-state lighting industry. Tools and standards will be developed at various levels to enable design and manufacturing of more reliable and cost effective LED based lighting solutions which can be brought...
White light-emitting diodes (LED) are widely applied in many fields for its special advantages compared with other light sources. Chip-scale-package (CSP) is one of the hotspots in the research of microelectronics, and also the main stream and development direction to the future package technology. Within a CSP, the solder layer between LED chip and substrate is usually achieved via reflow processes...
In the phosphor coating process of the phosphor-converted light-emitting diodes (pc-LEDs) packaging, the phosphors settle spontaneously due to the density difference between the phosphor particles (YAG-04, about 4800 kg/m3) and the silicone matrix (OE6550 A/B, about 1120 kg/m3). The phosphor sedimentation affects the phosphor distribution and changes the optical performance of pc-LEDs, such as the...
The SnSbNi solder pastes were reflowed at 270°C and 280°C between the MvpLED chip and the AlN ceramic substrate, and then the SnSbNi solder joints were aged respectively at 200°C for 1h and at 250°C for 3h. The interfacial microstructure and constituents were investigated by SEM and EDS. After the reflow reactions, a thin layer of IMCs was formed at the chip/solder and solder/substrate interfaces,...
A comprehensive study of the Ge1−xSnx alloy in the full composition range using state-of-the-art density functional theory methods has been performed. Various conclusions shedding new light on its properties, in relation to experiment, like gaps regimes, band offsets, and the Burstein-Moss effect, has been drawn.
Hybrid halide perovskite has made great advances for making new composition of materials, which have wide usage in advanced optoelectronic devices. Here we show amplified spontaneous emission (ASE) in a perovskite nanograting metasurface, defined by the cost effective nanoimprint lithography method which cannot typically be applied to hard, ionic based materials such as perovskite.
In this paper, we present our recent progress towards flexible nitride nanowire devices: we propose a method to combine high flexibility of polymer films with high quantum efficiency provided by nitride nanowires. The lift-off and transfer procedure allows to assemble free-standing layers of nanowire materials with different bandgaps without any constraint related to lattice-matching or growth condition...
Wide bandgap nitride semiconductors have attracted interest for next-generation devices in applications ranging from optoelectronics to power electronics. Device heterostructures are commonly grown on thermally- and lattice-mismatched substrates, which results in a large density of defects, incurring performance and lifetime limitations. Substrate technology remains a critical issue for the improvement...
Deep UV (DUV) light-emitting diodes (LEDs) are finding increased application in many areas including water purification and sterilization. Sub-270 nm emission is ideal for these applications since bacterial DNA absorbs strongly in this wavelength regime. To extract high energy photons (∼5 eV), the LED cladding regions must be transparent and therefore consist of high Aluminum content (>60%) n-...
High-throughput assembly of miniature wafer-fabricated packages onto panel substrates provides a manufacturing framework for high-performance multi-functional displays and other large-format systems. Control circuits, light emitters, sensors, and other micro-components formed in high-density arrays on wafers use a variety of processes and materials that do not easily translate to large-format panel...
A method to integrate III-V compound semiconductors (GaN HEMT, InGaN LED, InGaAs HEMT or InGaP LED) with Si-CMOS on a common Si substrate is demonstrated. The Si-CMOS layer is temporarily held on a Si handle wafer. Another III-V/Si substrate is then bonded to the Si-CMOS containing handle wafer. Finally, the handle wafer is released to realize the Si-CMOS on III-V/Si substrate. Through this method,...
Special chip designed and fabrication micro-device array LED in panel systems. It is transferred signals onto micro-LED slides. Addressed device structure chosen LED die, which is the principle of the use of bonding technology to LED fabric placed on a CMOS/MEMS substrate, followed by micro-LED array of each style. Special chip design signals generation way is in a short time. It is a great thrust...
Focused ultraviolet (UV) emission is an ideal configuration to achieve in-situ curing. Conventional UV light-emitting diode (LED) packages, such as ceramic substrate packages, cannot achieve focused UV emission because they possess no reflector and lens, which are required to converge light. Plastic reflectors may be used, but common LED packaging plastics suffer from low UV reflectance and UV degradation...
AlGaN-based deep-ultraviolet (DUV) light-emitting diodes (LEDs) suffer serious light extraction problems. In this work we report a sidewall reflection method to enhance the light extraction of AlGaN-based DUV LEDs. The method includes mesa micro array designs and on-chip high reflective metal pads for DUV light. The 278-nm LEDs using this method show a 30.% improvement in light output power (LOP)...
Graphene exhibits an extremely high in-plane thermal conductivity, which shows highly prospective value in thermal management and heat spreader application. In this work, graphene sheet was integrated into LED module as intermediate heat spreader with different schemes, and heat dissipation performance was measured and evaluated using standard InfraRed (IR) camera. The experimental data shows that...
The integration of direct bandgap III-V semiconductors on Si substrate can enable efficient light emitters, and many applications that need light sources would be benefited, such as lighting, display, photonic integrated circuits (PICs), and on-chip optical communications. AlGaInP that is lattice-matched to GaAs is an efficient light emitting material which emits red to yellow-green light, depending...
Next generation white lighting and displays request a combination of high efficient RGB (Red, Green, Blue) or RGYB (Red, Green, Blue, Yellow) LEDs as opposed to current white LEDs fabricated using the "blue LED +yellow phosphor" approach. A white lighting source fabricated in either a RGB or a RGBY manner could potentially provide not only highest efficiency but also best colour rendering...
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