Deep level defects in N-rich and In-rich InxGa1−XN: in composition dependence

This study focuses on the presence and electronic properties of deep levels in In- and N-rich InxGa1−xN materials with different growth temperature, causing the different In composition, grown by nitrogen plasma-assisted molecular beam epitaxy (PAMBE). Semi-transparent Ag/Au Schottky contacts were formed on the InxGa1−xN layers and the device performances has been investigated with varying In contents. Increase in the leakage current density with the increase of In content has been observed in both In- and N-rich samples. Deep level optical spectroscopy has shown three deeper levels in both In-rich and N-rich InxGa1−xN layers. 1.4-1.6 eV level below the conduction band has been observed in all the samples, while the energy values of the other deep levels varies by sample to sample. The deepest levels are found to be the most prominent with the concentration in the range of 1016 cm−3 for high In content InxGa1−xN for both In-rich and N-rich growth conditions. Almost 4-5 times higher total trap concentrations have been observed for higher In InxGa1−xN sample.