Identification of point defects in Ga(AI)NAs alloys

By employing the optically detected magnetic resonance (ODNM) technique, two different Ga-i defects, namely Ga-i-A and Ga-i-B, are found and identified in the investigated Ga(Al)NAs epilayers grown on GaAs substrates by molecular-beam epitaxy (NME). This finding shows that Ga interstitials are common intrinsic defects in various dilute nitrides. In addition to the Ga-i-related defects, "middle line" ODMR signals were observed at around g=2 and are suggested to arise from superposition of a defect with a single ODNM line and a defect with an unresolved HF structure. All defects studied are shown to act as non-radiative recombination centers, and are therefore harmful to performance of potential light-emitting devices based on the alloys.