It is essential that tomorrow’s optical networks are built with far more efficient components to prevent the continual ramp in internet traffic from significantly increasing global energy consumption. One promising device that will help in this endeavour is a 1310 nm VCSEL formed by fusing together active regions grown on InP wafers and mirrors formed on GaAs substrates, says Alexei Sirbu from Ecole Polytechnique Fédérale de Lausanne (EPFL) and Eli Kapon from EPFL and BeamExpress.
Packaging has its downsides: It increases the footprint and the price of a power MOSFET, while degrading its performance through unwanted increases in resistance and inductance. The best solution is to ditch the package, a step that allows GaN HEMTs to be cost-competitive with silicon incumbents, argues Alex Lidow from Efficient Power Conversion Corporation.
Talk of silicon completely displacing GaAs in the RF front-end of cellular phones is premature and dead wrong, argues TriQuint’s Phil Warder. In his view, the future will instead involve smart RF suppliers collaborating closely with OEMs and chipset partners to offer complete RF solutions that exploit the best technologies for each application.
As Nujira unveils its highest performing envelope tracking chip for mobile handsets yet, vice president Jeremy Hendy asserts the technology is ready for GaAs and CMOS power amplifiers. Compound Semiconductor reports.
Just when you thought Amonix was scaling down operations, the CPV system manufacturer comes back with a re-vamped manufacturing strategy and a cheaper module. Compound Semiconductor talks to founder, Vahan Garboushian, about the company's future.
A misconception is holding back the development and deployment of GaN devices that are built on silicon substrates. This platform is widely blamed for compromising blocking voltages, but it doesn’t: It is possible to make diodes and HEMTs on silicon that have breakdown voltages of well over 2 kV, according to Timothy Boles and Douglas Carlson from M/A-COM Technology Solutions, Tomas Palacios from MIT and Mike Soboroff from the US Department of Energy.
There are many options for improving the performance of III-V solar cells, including inserting quantum wells and dots to extend spectral coverage and adding nanoparticles and diffraction gratings to boost light trapping. Insights into all these approaches are outlined by Sudha Mokkapati, Samuel Turner, Haofeng Lu, Lan Fu, Hark Hoe Tan and Chennupati Jagadish from The Australian National University
To fulfil the tremendous potential of graphene, high-quality material must be shipped in significant volumes. One supplier looking to do just that is Graphensic, which has developed graphene-on SiC products for making structures for metrology, high-speed transistors and biosensors. Company founders Rositza Yakimova, Mikael Syväjärvi, and Tihomir Iakimov detail their progress.
Diversification lies at the heart of Kyma Technologies’ vision for its future. It first made a name for itself as a leading supplier of wide bandgap materials, but it is now expanding its offerings and has starting to provide plasma vapour deposition (PVD) equipment and photoconductive switches, explains the company chief executive officer, Keith Evans.
Photonic integrated circuits enable the construction of compact, highly functional components, but operation tends to be restricted to telecom wavelengths. We are now addressing this shortcoming by developing devices that operate further into the infrared, say imec's Dries Van Thourhout and Gunther Roelkens.
It’s great for business to adopt a holistic approach to sapphire manufacturing. When a firm begins with the processing of raw materials and ends with wafer polishing, it enables a trimming of manufacturing costs, the application of proprietary processes to many steps used in sapphire substrate production, and improvements to the reliability of product supply, argues Raja Parvez from Rubicon Technology.
Lasers and LEDs that are grown on semi-polar planes deliver very impressive performance at green wavelengths, but commercial success of these devices is hampered by a lack of affordable, high-quality substrates with appropriate orientations. To address this, a German team is developing various methods to make semi-polar material, and studying its properties in detail. Richard Stevenson reports.