Noise characteristics of InAs/GaSb superlattice infrared photodiodes

Abstract

Abstract A sophisticated noise measurement setup employing a switching unit to measure statistically relevant numbers of InAs/GaSb superlattice photodiodes has been developed. The noise current resolution limit of 20 fA Hz ‐1/2 enables the characterization of focal plane array‐sized InAs/GaSb superlattice homojunction photodiodes for the long‐wavelength infrared at 77 K. To resolve midwavelength infrared photodiodes a junction area of about (400 µm) 2 is required. Without switching unit and by using a dedicated low noise amplifier, noise currents down to 2 fA Hz ‐1/2 can be achieved, allowing the noise characterization of mid‐wavelength photodiodes with smaller junction areas. With this setup long‐wavelength and mid‐wavelength InAs/GaSb superlattice photodiodes, with generation‐recombination limited dark current behavior, are investigated at 77 K. The measured diode noise follows the theoretically predicted shot noise level within the white noise part of the spectra. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)