Two color InAs/InGaAs dots-in-a-well detector with background-limited performance at 91 K

Abstract

Normal incidence long wave infrared (λ c ∼9 μm) InAs/In 0.15 Ga 0.85 As dots-in-a-well detectors with background limited performance at 91 K, under f#1.7 300 K background irradiance, are reported. Two distinct peaks (λ p1 ∼4.2 μm and λ p2 ∼7.6 μm) are observed in the spectral response, which could possibly be due to a bound-to-continuum transition and a bound-to-bound transition, respectively. The operating wavelength of the detector can be varied by changing the width of the quantum well surrounding the quantum dots. Using calibrated blackbody measurements, the peak responsivity of the detector is measured to be 0.73 A/W (V b =−1.7 V at T=60 K).