Staff: P. Christol, J.P. Perez, J.B. Rodriguez
PhD students: M. Delmas (2012-2015) ; Q. Durlin (CIFRE-Défense DGA-Sofradir, 2014-2017) ; R. Alchaar (2016-2019) ; U. Zavala-Moran (CONACYT, 2017-2020), M. Bouschet (CIFRE Lynred, 2019-2022).
Projects: VITRAIL (PEA DGA 2013-2015), HOT-DETECTOR (PEA DGA 2015-2017), ESA (ESA contract 2016-2019), HOT-MWIR (ANR C24 2018-2022), CNES (R&T CNES 2019-2022), ONERA (ONERA contract 2019-2022)
Main collaborations : I. Ribet-Mohamed, ONERA-Palaiseau (France), N. Péré Laperne, Lynred (France), L. Höglund, IRnova (Sweden).
The objective is the fabrication and the study of high performance cooled infrared (IR) quantum detectors made of Ga-containing InAs/GaSb type II superlattices (T2SL) or Ga-free InAs/InAsSb T2SL in new barrier architectures. These Sb-based photodetectors should be able to improve the signal to noise ratio to satisfy the criteria of SWAP (Size, Weight and Power) requirements with high operating temperature (T > 150K) in the Midwave IR (MWIR 3-5µm) and to reach high performance in the longwave IR (LWIR 8-12µm) and Very Longwave (VLWIR l>12µm) spectral domains to address specific spatial or military applications.
Barrier structures (XBn or XBp) are now the usual design of antimonide-based (Sb-based) cooled IR quantum detectors. During the last period, MWIR Ga-free T2SL and LWIR/VLWIR Ga-containing T2SL have been studied.
To address the MWIR broadband and operate at temperature as high as 150K, InAs/InAsSb Ga-free T2SL in XBn configurations have been grown by MBE on GaSb substrate. In the framework of the ANR project HOT-MWIR, involving IES, LPENS, ILV, 3-5 Lab, ONERA and Lynred (ex Sofradir) the first demonstration of XBn Ga-free T2SL detector, using n-type AlAsSb alloy as barrier layer, has been reported. Compared to MWIR Ga-containing MWIR pin detector, such device permits an improvement of temperature operation, showing cut-off wavelength of 4.85 µm at 150K and exhibiting dark current density as low as 2×10-6 A/cm2 at 150K and Vbias = -200mV.
In the context of the ESA project, involving IES, IRnova and AIRBUS DS, Ga-containing InAs/GaSb T2SL XBp detectors focused the LWIR and VLWIR spectral domains. The first XBp detector structure, using p-type InAs/AlSb T2SL as barrier layer, has been fabricated and characterized. Normalized photoresponse spectra, dark current density (Jdark) and differential resistance area product (RdA) as a function of the voltage are connected in order to extract particular bias such as the operating bias Vop and the VGR bias for which the G-R current begins to dominate the dark current of the diode.
Next step for T2SL technology operating in the LWIR/VLWIR dedicated for space application is to evaluate radiation tolerance under proton fluence. In collaboration with AIRBUS DS, this objective is currently studied in a R&T CNES project.