Identification of point defects in Ga(Al)NAs alloys

By employing the optically detected magnetic resonance (ODMR) technique, two different Ga(ind i) defects, namely Ga(ind i)-A and Ga(ind i)-B, are found and identified in the investigated Ga(Al)NAs epilayers grown on GaAs substrates by molecular-beam epitaxy (MBE). This finding shows that Ga interstitials are common intrinsic defects in various dilute nitrides. In addition to the Ga(ind 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 ODMR 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.