The discovery of a large, composition-dependent bandgap bowing in dilute GaNAs alloys on GaAs has stimulated active research towards the development of novel electronic and optoelectronic devices. While the smaller nitrogen atoms reduce the lattice constant of GaNAs epilayers on GaAs, the bandgap is also dramatically reduced. This has enabled the development of commercial-quality GaInNAs vertical cavity surface emitting lasers (VCSELs) at the important telecommunications wavelength of 1.3um, for example.

More recently, we have developed GaAs-based edge-emitting lasers at 1.55um using quinary GaInNAsSb quantum-well active regions grown by molecular beam epitaxy (MBE). The devices produced at IMS have exhibited the first room-temperature continuous-wave operation at this wavelength, and have set new reliability benchmarks. In collaboration with the Institute of Photonics, Strathclyde, we have also demonstrated the first VCSELs at this wavelength under pulsed optical excitation.

In this presentation, the fundamental principles of dilute nitride and antimonide alloys will be introduced, with an emphasis on the epitaxial growth challenges. Optical properties of these materials will be discussed, including recent observations of inter-subband transitions. The wide applicability of these alloys will be illustrated using device results for lasers, detectors, heterojunction bipolar transistors and resonant tunneling structures, all of which have been developed in the IMS program.

Dr. Gupta has been developing MBE techniques and devices based on novel III-V materials since 2001 and is the coordinator of the Institute’s Mid and Near-IR III-V Lasers program. Previously at IMS, he studied rare-earth oxides and silicates as alternative gate dielectrics for silicon CMOS. He received his doctorate from Simon Fraser University, Vancouver, Canada in 1999 based on studies of single- and sub-monolayer InAs films in GaAs produced by metalorganic chemical vapor deposition. He is the co-author of 50 publications in peer-reviewed journals and a co-inventor of 1 US patent.