Objective
The first objective of the project is to demonstrate THz quantum cascade detectors (QCD). QCDs are formed by the repetition of active and extractor quantum well (QW) regions and rely on intersubband (ISB) absorption in the active QW and photo-excited electron transfer through the extractor from one period to the other. In contrast to existing THz quantum detectors such as GaAs QWIPs, these photovoltaic devices operate under zero bias and do not suffer from any dark current, which is one main advantage for increasing the operation temperature while benefiting from the maximum detectivity limited by the background (BLIP). Our target is to demonstrate THz QCDs with a responsivity larger than 100 mA/W and a BLIP temperature of 77 K at 12 THz.
A second related objective of the project is to make significant progress towards THz QC lasers in the GaN/AlGaN material system. We will make use of the advanced know-how acquired on the design, growth and processing of GaN-based THz QCD devices to develop electroluminescent sources. One first goal is to develop spectrally narrow THz light emitting devices at room temperature based on in-plane transport, which can find a number of applications because of their fast modulation capabilities. Our final target is to demonstrate stimulated gain under vertical transport using plasmonic waveguide resonators and lasing at cryogenic temperatures.
| Expected results | Success criterion | |||||||||||||||
| Demonstration of GaN-based THz QCDs | Peak detection adjustable in the 1-15 THz frequency range | |||||||||||||||
| High-performance GaN-based QCDs | Achievement of a peak responsivity =0.1 A/W and operating temperature for back-ground limited detectivity of 77 K at 12 THz (D*~4x1010 Jones) and 20 K at 3 THz (D*~5x1011 Jones) | |||||||||||||||
| Demonstration of GaN-based cascade THz light emitters | Experimental evidence of 1 µW THz electroluminescence under vertical transport | |||||||||||||||
| Demonstration of feasibility of THz QCLs | Experimental demonstration of stimulated gain in metallic plasmon waveguides | |||||||||||||||