Barrier detectors are designed to reduce the dark current associated with Shockley–Read (SR) processes and to decrease the influence of surface leakage current without impeding photocurrent (signal). As a consequence, the absence of a depletion region in barrier detectors offers a way to overcome the disadvantage of the large depletion dark current. Therefore, they are typically implemented in materials with relatively poor SR lifetimes, such as all III-V compounds. It is shown here that despite numerous advantages of III-V barrier detectors over present-day detection technologies, including reduced tunneling and surface leakage currents, normal-incidence absorption, and suppressed Auger recombination, the promise of a superior performance with these detectors in comparison with HgCdTe photodiodes has not been realized yet. The dark current density is higher than that of bulk HgCdTe photodiodes, especially in the mid-wavelength infrared range.