LIGHT SENSOR FOR FAR INFRARED (4-30 μm)
For detection of mid-infrared radiation in the range between 4-30µm there are several pos- sibilities. Detectors based on mercury cadmium telluride (MCT) are sensitive in the range up to 20µm. However, MCT is highly poisonous. Since MCT is not RoHS compliant, its use is widely prohibited. Further, structures exhibit a low uniformity due to a low vapor pressure of Hg. Therefore, photodetectors based on MCT suffer from a low yield due to defects and leaking currents.
We offer a new detector technology for infrared radiation between 4 and 30µm. It is the ideal candidate to replace MCT-detectors. This technology is based on a resonant tunneling structure for hole tunneling in the valence band. The structure consists of a p-doped layer as well as an absorption layer. The latter is a GaInAsSb layer being highly photosensitive in a range between 1.7µm and 5µm. Using a GaInSb/InAs-superlattice the detector can cover the range between 2.5µm and 30µm.
Figure: (a) three-dimensional sketch of the resonant tunneling diode (RTD) photodetector. (b) Schematic conduction (CB) and valence band (VB) profile under an applied bias voltage.
(1) Pfenning, A., Hartmann, F., Langer, F., Kamp, M., Höfling, S., & Worschech, L. (2016). Sensitivity of resonant tunneling diode photodetectors.
Nanotechnology, 27(35), 355202.