MCT-on-silicon negative luminescence devices with high efficiency

We used an InSb radiometric thermal imager to characterize the performance of 1'' X 1'' negative luminescent (NL) arrays. The devices grown on both CdZnTe (two arrays) and silicon (three arrays) as substrates have cut-off wavelengths ranging from 5.3 mum to 6.0 mum. The reverse-bias saturation current densities range from 0.3 A cm (lambda co = 5.3 mum) to 1 A cm (lambda co = 6.0 mum). The apparent array temperatures decrease by 37.9 K to 42.8 K under reverse bias, which corresponds to external NL efficiencies of 80-85%. Most of the inefficiency results from the non-ideal AR coating, whose reflectivity is approx 15% when weighted over the black body and atmospheric transmission spectra. It is highly encouraging that both the electrical and NL properties are slightly superior for the devices grown on silicon substrates.