Materials World Network: III-V Bismide Materials for IR and Mid IR Semiconductors

III-V compound semiconductor materials are increasingly important for the development of many modern materials applications and in particular optoelectronic and electronic devices. These include materials for laser diodes, light emitting diodes (LEDs), photovoltaics & photodetectors, avalanche photodiodes, THz emitters & detectors, heterojunction bipolar transistors, and spintronic devices. Over the years several elements from the III-V system have been investigated to advance these material systems in order to persistently progress towards superior devices and to exploit novel material properties for advanced device applications. It is particularly important and timely to develop new materials which improve the operating efficiency of devices and reduce energy consumption. For example, the unexpected runaway success of GaN alloys as a new class of semiconductor materials for LEDs (e.g. in solid-state lighting) and high temperature/high power electronics has inspired research into whether other previously overlooked semiconductor alloys offer similar opportunities for different applications. An example of a relatively unexplored family of semiconductor materials is the alloys of the heaviest naturally occurring group V element, bismuth. Bismuth is the heaviest non-radioactive element in the periodic table, and unusually for the heavy elements, it is non-toxic and relatively inexpensive, meaning it has found application in elemental form in fire-safety systems (due to its low melting point) and thermocouples. Furthermore, since spin orbit splitting increases super linearly with atomic number, Bi-alloys have a very large spin orbit splitting compared with conventional semiconductor alloys, and thus presents interesting opportunities for new types of electronic devices based on electron spin. Consequently III-V bismides offer many new prospects in the area of materials research and the opportunity to develop an innovative class of materials for the expansion of science and technology. Some of the strategic attributes offered by III-V bismide materials are: i) the potential to cover near infrared (IR) wavelengths up to 3 um on GaAs substrates and all wavelengths beyond 2 um on GaSb substrates, ii) a uniquely large spin orbit splitting which provides an opportunity for semiconductor spintronic devices, iii) a spin orbit band offset that is typically larger than bandgap energy which provides an opportunity to develop active materials with significantly reduced Auger recombination, iv) a small temperature dependence of the band gap energy that offers improved temperature stability for emitters and detectors, and v) the opportunity for band offset engineering that offers substantial improvement for hole confinement in GaSb based mid IR diode lasers. To further exploit and develop these various possibilities, an international team of theorists and experimentalists with expertise in materials and devices is proposed. This team is expected to rapidly advance science, technology, and education in the area of III-V bismide materials and devices for optoelectronic applications, the potential for which is very large.