AlGaAs Ambient Light Detectors With a Human-Eye Spectral Response

We report an AlGaAs ambient light detector with a spectral response matched to Commission Internationale de l´Eclairage (CIE) photopic luminosity function. The detector consists of an Al_0.6 Ga_0.4As PIN junction for main absorption, a two-step-four-section compositional grading structure centered in the junction for auxiliary absorption, and a built-in filtering structure on top of the PIN junction. The peak responsivity of the detector is 0.096 A/W at 558 nm, which corresponds to 164 pA/lux in photometric unit. The CIE defined spectral mismatch index f ₁ ^´ of the detector is as low as 5.8%.