Three themes dominated the discussions at the latest nitride meeting: the cause of LED droop; the best approach to plugging the green gap; and the development of higher-quality, lower-cost native substrates. Cambridge University researcher Michelle Moram reports from Jeju Island, Korea.
The European Commission is funding a multi-national project that aims to boost the performance of nitride-based transistors, pressure monitors and chemical sensors. Success could lead to creation of AlInN/GaN-based devices that probe the environment in jet engines, measure incredibly high pH levels, and deliver output powers of more than 1kW at 2 GHz. Richard Stevenson investigates.
Temperature uniformity in wafer processing has always been an area requiring accurate measurement and control in silicon based manufacturing. With new materials and scaling challenges the need for temperature control has increased to the point that any deviation from requirements can lead to manufacturing failure. Thomas Kupiszewski of Watlow discusses how thermal design analysis is used in improving existing processes and even extending the life of equipment.
Superluminescent diodes have been the poor relative of the photonics toolkit for many years. But Optical Coherence Tomography promises to change that, and quantum dot superluminescent diodes have the potential to be the ideal technology for this application, says Mark Hopkinson from the University of Sheffield, UK.
It’s been a roller coaster year for AkzoNobel’s High Purity Metalorganics division. Orders in the first quarter were incredibly weak, but the return of a burgeoning LED industry and great solar prospects are strongly reviving the business. Richard Stevenson talks to Michiel Floor, AkzoNobel’s global business manager of these products, about this division’s change in fortunes and other recent developments.
Shipments of GaAs chips for automotive radar will rise over the next few years thanks to the penetration of this technology into mid-price cars, such as the Volvo S80. However, sales are expected to falter by the middle of the next decade, due to tough competition from SiGe. Richard Stevenson reports.
Increasing the conversion efficiency of triple-junction solar cells will help to cut the cost of this form of power generation. One approach to higher efficiencies is to push the bandgaps of the sub-cells towards the theorectical ideal, which is approach that we have adopted at Fraunhofer ISE, says Frank Dimroth, Wolfgang Guter, and Andreas Bett.
DARPA is driving the development of ultra-high-frequency emitters and receivers based on InP HEMTs and HBTs. If successful, this effort could ultimately lead to the manufacture of imaging systems that enable helicopter pilots to navigate with greater confidence in foggy, smoky and dusty conditions. Richard Stevenson investigates.
It is popularly observed that the photonic industry actually survives on differentiation in device design and process in order to show superior performance. With hundreds of semiconductor laser designs that emit at 1550 nm or even 1310 nm, when will the industry agree on a common platform? By Michael Lebby, President and CEO, OIDA.
A Korean partnership has joined the controversial debate over the origin of LED droop. It claims that its sophisticated approach to curve fitting of experimental data demonstrates that Auger recombination only makes a small contribution to droop, the decline in GaN LED external quantum efficiency at higher current densities.
Sales of LED-backlit TVs will rocket over the next fives years, leading to domination of this market. Richard Stevenson quizzes Strategies Unlimited’s Robert Steele on the reasons behind this tremendous growth, and its implications for LED chipmakers and MOCVD tool manufacturers.
Researchers from Yamaguchi University, Japan, have produced semi-polar (1122) GaN on a maskless r-plane patterned sapphire surface. Their advance could help to spur the development of green-emitting devices that are grown on the semi-polar planes of GaN. These faces enable the fabrication of epistructures that are not hampered by strong internal electric fields, and they facilitate the growth of InGaN layers with a high enough indium content for green emission.
A commercially viable GaN LED was an incredibly hard nut to crack that required the development of a buffer layer and a novel approach to p-type doping. But 20 years ago it all came together. Richard Stevenson looks back at the device’s birth.
Mode-locked lasers (MLLs) are effective sources of periodic trans of coherent optical pulses and are fundamental components in a range of optical communications and spectroscopy applications. Especially, integrated semiconductor lasers have advantages over other forms of laser since their waveguide structure concentrates the optical intensity into the active medium, and the short cavity lengths typically lead to repetition rates in the range 40 GHz to 2 THz.
Predictions of long-term growth in the photovoltaics market are not just good news for triple-junction solar cell makers. SiC diode and transistor manufacturers are also set to benefit, because these chips can drive up the efficiencies of converters that transform the DC output from cells into the AC form needed for the grid. Richard Stevenson reports.
Tube heaters are applied any time where liquid or gaseous media are being delivered through tubes. These tube heaters do have a critical impact on process results when used with thermal sensitive media or processes and contribute to the extension of maintenance cycles in the facility. Pump- and Gas Line heaters, as introduced in this article, were developed especially for those kinds of applications.
Throughout the history of mankind, materials have been a defining factor in terms of tools and technologies. From the Stone Age, through the Bronze and Iron ages, materials have played a key role in human advancement. IQE’s Richard Hammond and Rob Harper take a look at the way modern day materials continue to define technological progress.
It is taken for granted that lowering the defect density in GaN-based light emitters improves their performance. But photoluminescence studies on GaN powders suggests that defects might actually be a good thing, says Birgit Schwenzer from the University of California, Santa Barbara.
The debate over the origin of LED droop rages on, with recent simulations contradicting earlier calculations and claiming that direct Auger recombination is the primary cause. Richard Stevenson investigates.