Characterization of spectral response of a quantum dots-in-a-well infrared focal plane array

Abstract

Spectral characterization of a novel single bump, two-color InAs/InGaAs quantum dots-in-a-well (DWELL) infrared focal plane array (FPA) was undertaken and reported here. The hypothesis of the study is that the FPA will exhibit bias-tunable spectral response. Broadband and two-color performance measures of the DWELL FPA are discussed and presented. The DWELL structure is a hybrid of a quantum dot (QD) photodetector consisting of an active region composed of InAs quantum dots embedded in InGaAs quantum wells. The DWELL FPA demonstrates mid-wave infrared (MWIR) and long-wave infrared (LWIR) performance believed to be attributed to transitions from bound states in the dot to higher and lower lying energy states in the quantum well, respectively. The DWELL samples were grown by molecular beam epitaxy (MBE) and fabricated into 320 x 256 focal plane arrays with indium bumps via standard lithography at the University of New Mexico (UNM). The samples were hybridized to Indigo Systems Corporation ISC9705 read out integrated circuits and investigated with a SE-IR Corporation CamIRa\u2122 test system. The DWELL FPA exhibited temporal noise equivalent difference in temperature (NEDT) values of 43mK and 63mK (MWIR and LWIR respectively) at 77K

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