Extended Short-Wave Photodiode based on CdSe/HgTe/Ag2Te Stack with High Internal Efficiency
Résumé
Nanocrystal integration into focal plane arrays requires the development of new photodiode designs combining an efficient charge dissociation with a low dark current. Previously reported architectures based on HgTe/Ag2Te stacks appear to be sub-optimal for cutoff wavelengths below 2.5 µm. Here, we show that the introduction of a thin and strongly coupled CdSe layer acting as an electron transport layer and a unipolar barrier drastically improves the electrical performances. This diode achieves a responsivity as high as 0.8 A•W-1 , corresponding to an internal efficiency above 90 % for a 2 µm cutoff wavelength. The specific detectivity is close to 10 11 Jones at room temperature and reaches 9x10 11 Jones at 200 K, the highest value reported for HgTe nanocrystal-based photodiode with operation around 2 µm. The diode time response can be as short as 200 ns and appears to be limited by band bending dynamics as revealed by time-resolved photoemission measurements.
| Origine | Fichiers produits par l'(les) auteur(s) |
|---|