In the Brazilian Army there is a strong demand for the development of national infrared detectors for use in many applications subjected to severe trade restrictions, like infrared imaging systems for night vision, missile guidance, sight systems, etc. The aim of this work was to develop far- infrared photodetectors for 10µm, based on semiconductor structures of GaAs/AlGaAs multi-quantum wells using intraband transitions. The materials were grown by metalorganic vapor phase epitaxy (MOVPE). The calibration of the growing parameters was done by x ray diffraction, Hall effect, and photoluminescence measurements. Since intraband transition of light is not possible to normal incidence, due to selection rules, two coupling techniques were applied: waveguide geometry with 45o incidence on the edge, and metalized diffraction gratings. The produced detectors were characterized in terms of dark current, optical absorption and spectral response. Infrared measurements were made using FTIR spectroscopy. A GaAs/AlGaAs photodetector was obtained. The photocurrent through the electrical contacts of the device showed a peak at 9µm. The results are promising in the sense of revealing the possibility of producing national infrared photodetectors for many applications (defense, medicine, astronomy, telecommunications, etc).