Structural, surface potential and optical studies of AlGaN based double heterostructures irradiated by 120Â MeV Si9+ swift heavy ions

The Al0.33Ga0.77N/Al0.14Ga0.86N based double heterostructure was irradiated using Si9+ ion at room temperature (RT) and liquid nitrogen temperature (LNT) with four dissimilar ion fluence. The effect of Si9+ ion irradiation in dislocation densities and in-plane strain of GaN layer were discussed. The in-plane strain values of AlxGa1-xN layers were calculated from asymmetric reciprocal space mapping (RSM). The surface modification and the variation in phase shift on Al0.33Ga0.77N surfaces due to the irradiation were measured by Electrostatic Force Microscopy (EFM). The capacitance of the tip-sample system was determined from EFM. The band edge emissions of heterostructures were measured by the room temperature phototluminescence (PL) and the shift in the Al0.14Ga0.86N active layer emission peaks towards the low energy side at low fluence ion irradiation has been noted.