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Technical Insights


Friday 16th October 2009
A partnership between Asif Khan’s group at the University of South Carolina and its spin-off, Nitek, claim to have developed ultra-violet LEDs with a record output for a single chip.
Wednesday 14th October 2009
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.
Tuesday 13th October 2009
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.
Monday 12th October 2009
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.
Sunday 11th October 2009
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.
Tuesday 1st September 2009
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.
Tuesday 1st September 2009
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.
Tuesday 1st September 2009
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.
Tuesday 1st September 2009
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.
Tuesday 1st September 2009
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.
Tuesday 1st September 2009
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.
Tuesday 1st September 2009
Japanese substrate manufacturer Sumitomo has won the race for the first truly green nitride laser with a 531 nm semi-polar device that it announced on 17 July, 2009.
Wednesday 1st July 2009
Researchers at Oki Electric say that they have broken the output power density record for a high-voltage GaN HEMT built on silicon.
Wednesday 1st July 2009
As microchips inexorably decrease in size and enter the quantum regime, can single molecules ever replace silicon-based components? Douglas Natelson reports.
Wednesday 1st July 2009
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.
Wednesday 1st July 2009
AmberWave Systems has a novel technique for creating high-quality films of germanium and III-Vs on silicon – aspect ratio trapping. This involves epitaxial growth into trenches in a SiO2 layer and promises faster computer processors, say James Fiorenza, Mark Carroll and Anthony Lochtefeld.
Wednesday 1st July 2009
When metal electrodes are placed on the top of an LED, they reduce its emission area and increase internal absorption. But both of these problems can be completely eradicated with a buried n-type contact, say Osram Opto Semiconductors’ Berthold Hahn, Karl Engl and Markus Klein.
Wednesday 1st July 2009
One option for relieving the ever increasing strain on optical networks is to move to far higher bit rates. A European effort called HECTO has adopted that stance and developed 100 Gbit/s Ethernet transmitter chips based on InP, says project leader Urban Westergreen.
Wednesday 1st July 2009
Ian Ferguson and co-workers at Georgia Institute of Technology have produced crackfree GaN-on-silicon LEDs that feature an Al2O3 interlayer and produce similar internal quantum efficiencies to controls grown on sapphire.
Wednesday 1st July 2009
InP MOSFETs with a HfO2 gate dielectric can deliver higher drive current, higher transconductance and a lower gate leakage if they contain a silicon passivation layer, according to researchers at the University of Texas at Austin.
Monday 15th June 2009
The NASDAQ stock exchange has lost 40% of its value in the last 12 months, and the shares of most III-V players have fared worse. Well chosen acquisitions and manufacturing efficiency separate the winners and losers, finds Andy Extance.
Monday 15th June 2009
As recent as 2002, China imported all of its LED chips. It is now meeting half of this demand with domestic production and making the transition from incandescents to solid-state lighting. Richard Stevenson catches up with progress.
Monday 15th June 2009
Typically based on III-V solar cells, concentrated photovoltaics has the potential to be a fantastic source of renewable energy. But in a world where private finance has all but disappeared, Michael Hatcher wonders whether this fledgling industry has a future.
Monday 15th June 2009
Conventional LEDs that are used for solid-state lighting have to be connected to an AC-to-DC converter. But this bulky power supply impacts efficiency and reliability, and can be discarded by turning to Epistar's AC-LEDs that feature on-chip rectification circuits, says Carson Hsieh.

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