Study of new types of detectors in the SWIR: extension of the operating band beyond 1.7μm

Abstract

In recent years, an interest in the detection of the Short Wave Infra-Red (SWIR) band has grown. On the ground, the development of telescopes (ELTs) requires the construction of large focal planes in the SWIR for imaging, spectroscopy, or wavefront sensing applications. In space, the SWIR band can have many applications whether for communications or for imaging space and earth. The state-of-the-art III-V detectors in the SWIR are InGaAs photodiodes on InP substrate that are limited by a 1.7 µm cut-off wavelength. Superlattice (SL) based detectors, that have been increasingly studied in recent years, make it possible to reach new cut-off wavelengths. Starting from the InGaAs on InP detector technology that has been mastered for more than ten years by THALES, the III-V Lab we propose to extend the detection range beyond 1.7 µm by introducing a SL in the active region of an InGaAs photodiode. We will present the results obtained up to 2.6 µm, as well as the solutions implemented to limit the carrier localization in the superlattice and the associated QE degradation. We will also discuss the consequence of minority carrier lifetime on the performance and the consequence of localization on MTF.