High-detectivity, normal-incidence, mid-infrared (λ∼4 μm)InAs/GaAs quantum-dot detector operating at 150 K

Abstract

Normal-incidence InAs/GaAs quantum-dot detectors have been grown, fabricated, and characterized for mid-infrared detection in the temperature range from 78 to 150 K. Due to the presence of an Al0.3Ga0.7As current blocking layer in the heterostructure, the dark current is very low, and at T=100 K, Idark=1.7 pA for Vbias=0.1 V. The peak of the spectral response curve is at λ∼4 μm, with Δλ/λ=0.3 and Vbias=0.1 V. At T=100 K, for Vbias=0.3 V, the peak detectivity, D*, is 3×109 cm Hz1/2/W, and the peak responsivity, Rp, is 2 mA/W with a photoconductive gain of g=18.