Noise performance analysis of MWIR InAs/GaSb superlattice pin photodiodes

Abstract

We report the full electrooptical characterization of a MWIR InAs/GaSb superlattice (SL) pin photodiode, including dark current, noise, spectral response and quantum efficiency measurements. The SL structure was made of 8 InAs monolayers (MLs) and 8 GaSb MLs, with a total thickness of 3μm. It exhibits a cut-off wavelength of 4.55 μm at 77K. Dark current measurements reveal a diffusion-limited behavior for temperatures higher than 95K, and a R0A value of 1x10 6 Ωcm 2 at 77K. Noise measurements were performed under dark conditions and are interpreted in this paper. The results show that the SL detector remains Schottky noise-limited up to a bias voltage of -600mV and that 1/f noise is not present above 6Hz. Spectral response revealed that the cut-off wavelength increases from 4.48μm to 4.91μm when the temperature increases from 12K to 170K. The quantum efficiency in photovoltaic mode and at 77K is 25% (3μm-thick active zone device, single pass and without any antireflection coating). All these electrooptical performances confirm the high quality of the MWIR SL pin photodiode under test.