Effect of In implantation and annealing on the lattice disorder and nano-mechanical properties of GaN

► In implanted GaN is studied by Raman spectroscopy, RBS and nano-indentation. ► Phonon coherence length decreases in accordance to hardness and elastic modulus. ► Elastoplastic behavior is observed at low and plastic at high fluences. ► Annealing is more effective at fluences that do not cause complete amorphization. ► At high fluences annealing results in redistribution of atomic species.