A PIN photodiode under development in France at Thomson-CSF of Orsay and École Polytechnique of Palaiseau may challenge the place of thermal imagers such as microbolometers and pyroelectric devices in IR sensing applications. The researchers suggest that the InAsSb device, unlike other mid-IR photovoltaic detectors, will operate in the 3- to 5-µm atmospheric window without cooling. Reporting in the July 17 issue of Applied Physics Letters, the researchers used a molecular beam epitaxy system with reflection high-energy-electron diffraction to grow the detector. They suggest that increasing the gap of the n-doped barrier and using back illumination will improve the detectivity of the device at 300 K, which was measured at 3.39 µm and 250 K.