Novel growth techniques are helping to spur the output of deep ultra-violet LEDs to levels that are suitable for purifying water at more than a liter per minute, says Tim Bettles from Sensors Electronic Technology.
Adding a tiny probe to an IR microscope improves its temperature measurement capability, in turn giving new insights into the local heating profile of HEMTs and LEDs, according to a UK team comprising Chris Oxley, Richard Hopper, Dominic Prime, Mark Leaper and Gwynne Evans from De Montfort University and Andrew Levick from the National Physical Laboratory.
Novel chip geometries, such as triangular and hexagonal devices, can deliver massive increases in light extraction by cutting optical confinement in both the vertical and horizontal directions, says Hoi Wai Choi from the Semiconductor Lighting and Display Laboratory at The University of Hong Kong.
Silicon extreme ultraviolet detector arrays require non-standard methods to be prevented from receiving longer wavelength radiation, e.g. by using multiple filters. Switching to AlGaN equivalents increases robustness and eliminates the need to block out visible and infrared light, which in turn boosts detector performance, say IMEC’s Pawel Malinowski, Kyriaki Minoglou and Piet De Moor.
In order to become a successor to silicon CMOS technology, III-V transistors must be built on silicon substrates that are large enough to be processed by VLSI toolsets. Sematech has done just this by fabricating InGaAs MOSFETs on 200 mm silicon (100) using state-of-the-art silicon foundry tools. Richard Stevenson investigates.
Low-resistance channel contacts that speed transistors to record-breaking frequencies, localized boron doping that boosts blocking voltages and studies of HEMT ageing mechanisms all featured at the latest International Electron Devices Meeting. Richard Stevenson reports.
There are tremendous differences between the laser and the transistor, but it is possible to draw their attributes together by building a transistor laser. This novel device that produces its electrical and optical outputs simultaneously promises to revolutionize data transfer, enabling new architectures capable of operating at incredibly high bit rates, says Milton Feng from the University of Illinois, Urbana-Champaign.
Quantum dot infrared photodetectors suffer from strain in their nanostructures that culminates in various performance-degrading defects. However, many of these defects can be avoided by turning to a novel, strain-free growth method based on the deposition of droplets, says Jiang Wu from University of Arkansas Fayetteville.
Substantial reductions in chip production costs will spur the uptake of LED-based solidstate lighting. One way to do this is to start to manufacture these emitters with multi-wafer 6-inch tools that set a new benchmark for reproducibility, argues Aixtron’s Rainer Beccard.
An ensemble of spatially distributed III-nitride quantum dots can produce the broad, visible emission that is desirable for ambient lighting and the growth of crops, says Soh Chew Beng, Chua Soo Jin and Liu Wei from the Singapore Institute of Materials Research and Engineering.
The fast moving HB LED sector is starting discussions to consider the kinds of consistent materials characterization, testing protocols, tool interoperability, or other common practices that typically enable a mature high volume industry, reports Paula Doe from SEMI.
Due to a very small depth of focus, standard photolithography techniques have insufficient fidelity for defining photonic crystal structures on LED epiwafers. But highquality, large-scale patterning is possible by turning to a novel self-imaging photolithography technique, say Harun Solak, Christian Dais and Francis Clube from Eulitha.
POLISH GaN substrate manufacturer Ammono has unveiled characteristics of its semi-polar (2021) substrates. This cut of GaN is a promising candidate for the production of green lasers. Last summer, engineers at Sumitomo produced a 531 nm edge-emitter by exploiting the relatively high indium incorporation in InGaN quantum wells grown on this plane, plus the built-in electric fields that push emission to longer wavelengths.
A GERMAN team claims to have broken the record for data transmission from an oxideconfined 980 nm VCSEL operating at 85 °C. Their device, which is capable of 25 Gbit/s operation at that elevated temperature, is an ideal source for very short optical links in high performance computers, according to the researchers from the Technical University of Berlin and VI Systems.
CURVE fitting with the standard equation for carrier recombination in an LED shows that Auger recombination cannot, by itself, account for droop, the decline in device efficiency at high drive currents. That’s the claim of a partnership between Rensselaer Polytechnic Institute (RPI), Sandia National Laboratories and Samsung LED.
The use of LEDs is already widespread in consumer electronics, appliances, and other products. Single LEDs are seemingly ubiquitous; LED assemblies are widely used in mobile electronics, computer displays, and televisions. We can expect that LEDs will spread through industrial lighting and into the general lighting of our homes. By Ryan Clement and Robin Gardiner, at MATHESON.
Physical vapor transport can produce high-quality 2-inch AlN crystals with low dislocation densities. Substrates sliced from these crystals provide an ideal platform for the growth of ultraviolet LEDs, lasers and RF devices, says a team from Nitride Crystals.
Researchers have found that GaN Gate-Injection Transistors (GITs) could remarkably reduce the energy consumption in power conversion systems, since they have inherently low on-state resistance and low switching losses.