High-Performance Very Long Wave Infrared Quantum Cascade Detector Grown by MOCVD

We present a very long wave infrared (VLWIR) quantum cascade detector (QCD) optimized for the extraction region grown by metal organic chemical vapor deposition (MOCVD). The wave function of high-energy states has been tailored into a funnel-shaped miniband structure. This design accelerates the extraction and collection of electrons, thereby enhancing the device's extraction efficiency, with a theoretical calculation value of 91%. Besides, this miniband extraction scheme also increases the number of well barrier pairs between the ground state and the longitudinal optical (LO) phonon step level. The electron loss caused by thermal backfilling and thermally activated leakage can be effectively reduced. For a 200~\mu m \times 200~\mu m mesa device from a 4-inch wafer, a peak responsivity of 66 mA/W and a peak specific detectivity of 1.4 \times 10^{11} Jones were obtained at 30 K, with the maximum operating temperature persists up to 170 K.