W-Structured Type-II Superlattice Long-Wave Infrared Photodiodes with High Quantum Efficiency
NAVAL RESEARCH LAB WASHINGTON DC
Pagination or Media Count:
Results are presented for an enhanced type-II W-structured superlattice WSL photodiode with an 11.3 micron cutoff and 34 external quantum efficiency at 8.6 microns operating at 80 K. The new WSL design employs quaternary Al0.4Ga0.49In0.11Sb barrier layers to improve collection efficiency by increasing minority-carrier mobility. By fitting the quantum efficiencies of a series of p-i-n WSL photodiodes with background-doped i-region thicknesses varying from 1 to 4 microns, the authors determine that the minority-carrier electron diffusion length is 3.5 microns. The structures were grown on semitransparent n-GaSb substrates that contributed a 35-55 gain in quantum efficiency from multiple internal reflections.
- Electrical and Electronic Equipment
- Solid State Physics