Medium-wavelength, normal-incidence, p-type Si/SiGe quantum well infrared photodetector with background limited performance up to 85 K

TLDR: In this article, a pseudomorphic p-type Si0.64Ge0.36/Si quantum well infrared photodetector is presented, which exhibits a photoresponse between 3 and 8 μm with a peak responsivity of Rp=76 mA/W, at a peak wavelength of λp=5 μm, resulting in a detectivity as high as Dλ*=2×1010 cm√Hz/W at a temperature of T=77 K.

Abstract: The detector characteristics of a pseudomorphic p‐type Si0.64Ge0.36/Si quantum well infrared photodetector are reported. The device exhibits a photoresponse between 3 and 8 μm with a peak responsivity of Rp=76 mA/W, at a peak wavelength of λp=5 μm, resulting in a detectivity as high as Dλ*=2×1010 cm√Hz/W at a temperature of T=77 K. Background limited infrared performance is achieved up to T=85 K. Investigation of the polarization dependence shows that in‐plane polarized radiation produces the largest photoresponse, thus making normal‐incidence detection feasible. The relevant optical transitions are analyzed on the basis of a self‐consistent 6‐band Luttinger–Kohn calculation including the in‐plane dispersion.