A systematic study was made of the influence of the growth temperature upon the point defect landscape in metal-organic chemical vapour deposited InN. State-of-the-art InN layers were grown at 500 to 550C and positron annihilation spectroscopy was used to investigate the incorporation of vacancy defects during the growth process. It was found that a decrease of the growth temperature below 550C led to increasing free carrier concentrations and lower mobilities. At the same time, positron measurements observed an enhanced introduction of mixed In-N vacancy complexes which gather preferentially at the interface between the InN layer and the GaN template. As the measured In vacancy concentration seemed too low to promote efficient defect complexing, it suggested an increased formation of N vacancies at low temperature growth through insufficient cracking of NH3, which might be responsible for the observed increase in the free carrier concentration.

Point Defect Evolution in Low-Temperature MOCVD Growth of InN. C.Rauch, Ö.Tuna, C.Giesen, M.Heuken, F.Tuomisto: Physica Status Solidi A, 2012, 209[1], 87-90