Résumé
Symmetric and asymmetric mid-wavelength infrared (MWIR) InAs/GaSb superlattice (SL) pin photodiode were fabricated by Molecular Beam Epitaxy (MBE) on p-type GaSb substrate and characterized as a function of temperature. The symmetric SL structure was made of 8 InAs monolayers (MLs) and 8 GaSb MLs and exhibits at 80K a cut-off wavelength (lambda c) of 4.5 mu m, while the asymmetric SL design was composed of 7.5 InAs MLs and 3.5 GaSb MLs for lambda c = 5.5 mu m at 80K. Optical characterizations made of photoluminescence as a function of temperature and room temperature absorption spectra were performed on these two kinds of structures. Several electrical characterizations including dark current and capacitance-voltage measurements were also carried out on single detectors in the temperature range [77K-300K]. Results obtained were compared and analyzed in order to define optimized SL structure design for the high performance in the MWIR domain.