The nanoMIR group develops a number of III-Sb-based lasers: GaInAsSb/AlGaAsSb quantum well laser diodes, GaInSb/InAs interband cascade lasers and InAs/AlSb quantum cascade lasers. Combining these three systems allows covering the whole wavelength range from 1.5 µm to 25 µm. GaAs-based QCLs are investigated for THz emission. Mid-IR DFB and VCSELs deliver the single frequency emission needed for gas analysis.
The staggered type-II, i.e. type-III, alignment at InAs-GaSb interfaces allows controlling the cut-off wavelength of InAs/GaSb type-II superlattices (T2SLs) from the short- to the long-IR range simply by changing the individual layer thickness. So-called “Ga-free” InAs/InAsSb T2SLs represent an alternative option. The nanoMIR group investigates both types of photodetectors for IR imaging.
The mid-IR wavelength range exhibits transparence windows of the atmosphere and fingerprint absorption lines of a number of interesting – whether positively or negatively – gases. It is the best wavelength range to develop sensing systems based on tunable absorption spectroscopy. The nanoMIR group works on such systems, focusing lately on quartz-enhanced photo-acoustic spectroscopy.
Highly doped semiconductors based on III-Sbs are used to overcome the limitations of gold and silver as traditional materials in the field. The main topics developed are biosensing integrated in microfluidic circuits, thermal emission with complex metamaterial heterostructures and gap-plasmon structures for mid-IR applications.
Integrating III-V semiconductors and devices with the Si technology offers the promise to benefit from the best of both technologies. The nanoMIR group investigates the epitaxial integration of III-Sb-based optoelectronic devices on Si substrates, where the devices are directly grown on Si. It has also an action in the heterogeneous integration, where devices are bonded on the Si substrate or PIC.
The objective of the nanoMIR is also to develop new applications of the III-Sb technology. For example, upstream work has been recently carried-out on GaSb-based non-linear heterostructures, on topological insulator phases, on Novel diagnostic tools for nano-characterization of photonic devices, or on whispering gallery mode lasers, to name but a few.