In-vacancies in Si-doped InN

The introduction of vacancy type point defects by Si doping in InN grown by plasma-assisted molecular beam epitaxy was studied using a monoenergetic positron beam. With the combination of positron lifetime and Doppler broadening measurements, compensating In-vacancy (V(In)) acceptors were identified in the material. For increasing Si doping an enhanced formation of V(In), defects was observed, up to a concentration of c(V) = 7 x 10(17) cm(-3) in the highest doped sample (n(e) = 6.6 x 10(20) cm(-3)). A strong inhomogeneity of the defect profile with a significant increase of the V(In), concentration toward the layer/substrate interface could be detected. Additionally, larger vacancy clusters containing several V(In) are formed in the proximity of the interface. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim