Quantum cascade detectors are semi-conductor devices where infrared photons are absorbed in nanometric quantum wells on a picosecond timescale. These high performance infrared detectors are good candidates for thermographic and spectroscopic applications. To study electronic transport in these structures, one must organize the continuum of times and scales that span from the quantum phenomenon to the macroscopic device. In this thesis, we have shown that quantum coherent times and semi-classical scattering times must be taken properly into account to model the signal related quantities (current and noise). The so-called independence of Johnson ad shot noises in these structures is then discussed. They are proven to be the short and long time limits of a single phenomenon, ie the scattering of quantized charges. As a result, noise is calculated from quantum principles for the first time in intersubband structures. Lastly, the complete description of electronic transport enables us to discuss about the potentialities of this technology.
