Low-bias, high-temperature performance of a normal-incidence InAs/GaAs vertical quantum-dot infrared photodetector with a current-blocking barrier

The growth, fabrication, and characterization of a low-bias, high-temperature, InAs/GaAs vertical quantum dot infrared photodetector with a single Al0.3Ga0.7As current-blocking barrier are described and discussed. A specific detectivity ≈3×109 cm Hz1/2/W is measured at normal incidence for a detector temperature of 100 K at a bias of 0.2 V, and detector characteristics are measured for temperatures as high as 150 K. The equivalence of the activation energy and photoionization energy for thermionic emission in quantum dots is also verified. The superior low bias performance of the photodetector ensures its compatibility with commercially available silicon read-out circuits necessary for the fabrication of a focal plane array.