Thin films of aluminum nitride (AIN) doped with samarium (Sm) are deposited on silicon (100) substrates at 77 K by rf magnetron sputtering method. 200-400 nm thick films are grown at 100-200 watts RF power and 5-8 mTorr nitrogen, using a metal target of Al with Sm. Photoluminescence is performed using a 488 nm laser beam and two peaks are observed in Sm at 598 nm and 707 nm as a result of 4G5/2→6H7/2, and 4G5/2→6H11/2 transitions. Polarization studies are performed using an σ+ polarized laser. Both σ+ and σ- polarization exists. However a- polarization is dominant, showing that spin up electrons are the majority charge carriers. The existence of a+ and a- polarization at the same time further reveals that light holes and heavy holes are taking part together in every transition. Copyright © 2010 American Scientific Publishers All rights reserved.