The ultimate ability of an infrared detector to sense radiation and subsequently yield a measurable output signal is intimately related to the basic physical properties and transport mechanisms of the detector material. While spectral response measurements provide a monitor on the ultimate device performance and can yield information on the detector interface physics, still further insight into the devices is provided by an investigation of their electrical properties. An epitaxial thin film IV-VI detector technology providing both self-filtering and multicolor capability has been developed at the Naval Surface Weapons. Center (NSWC). Measurements have been made of a number of basic electrical characteristics of a series of these photodiodes, including their I-V, C-V and R0A-T dependencies. This has yielded information on the barrier profiles and current conduction mechanisms of these devices which is directly related to their optical sensing ability. Device performance has been found to be distinctly improved or degraded with thermal cycling, depending on the detector material used. These results can be correlated with lattice-matching investigations made on these detectors.