Guest Editorial

Abstract

It is our pleasure to introduce this special issue of IET Optoelectronics, focussed on Semiconductor Optoelectronics. An issue on this theme is published once a year and is linked to the Semiconductor and Integrated OptoElectronics (SIOE) conference held in Cardiff. SIOE 2014 was the 28th SIOE conference and featured an exciting programme that demonstrates the continuing evolution of Semiconductor Integrated Optoelectronics. A key trend in semiconductor optoelectronics that continues to develop is the increasing drive towards integration of materials and integration of functions. While much work still focusses on device performance, it is now almost always done in the context of the integrated system. Energy efficiency or “green photonics” also now features prominently and sometimes the two trends are combined. For example, both are used in the case of silicon photonics or for photonics integrated with III-V electronics where heat dissipation is the critical and limiting factor. Both of these trends are a result of focussing on societal issues and, at a time when research funding is in short supply generally and proposals must demonstrate impact, we are very fortunate as a community to be participating in a field with such a demonstrable importance for society at large. In this issue we attempt to give you a flavour of SIOE with examples of most of the important topic areas. You will notice that many of these address the trends identified above. In green photonics, recent developments in quantum dot (QD) based solar cells, covering material growth and the impact of QD carrier dynamics on device performance are addressed. In integration, overcoming the issue of crosstalk in coupled ring resonators, investigation of QD-in-a-well structures for semiconductor optical amplifiers, and laser diodes with low far-field divergence for applications in on-chip sensors are discussed. Finally, our invited paper which describes work with integrated functionality, covers some interesting physics and reports on the design and characterisation of innovative laser-active non-linear sources. The devices described make use of parametric down-conversion for producing radiation in the near-IR and difference frequency generation between two near-IR whispering-gallery modes for THz emission. We would like to thank all of the authors who submitted papers for the special issue, which works to a relatively short timescale in the manner of a conference proceedings but which insists upon fully expanded journal papers that have passed comprehensive scrutiny. We also thank the referees for their careful and constructive comments. We will leave you to enjoy this selection of papers with the hope that we will see you at SIOE in 2015. Sam Shutts is a research associate in the School of Physics and Astronomy at Cardiff University. He is involved with the design, fabrication and characterisation of semiconductor light emitting devices. His current research interests include quantum dot lasers structures grown on Si, dual-wavelength sources, InGaN optical devices and THz emission via difference frequency generation. Peter Smowton is Professor of Semiconductor Optoelectronics in the School of Physics and Astronomy at Cardiff University. His interests include the design, fabrication and characterisation of optoelectronic devices. Current research topics include quantum dot lasers, integrated optoelectronics and the physics of InGaN light emitting devices.