Experimental and computational analysis of transition metal ion-doped AlInN/GaN thin films

Abstract

To study ion beam modification on the structural and magnetic properties of metal organic chemical vapor deposition (MOCVD)-grown wurtzite AlInN layers, 200 keV ions of transition metals (TM) Cr, Mn, Co and V were implanted at doses of 5 × 10¹⁴, 5 × 10¹⁵ and 5 × 10¹⁶ cm⁻² into AlInN/GaN thin films. The structural properties of the materials were studied by X-ray diffraction (XRD) and Rutherford backscattering spectroscopy (RBS) techniques. XRD analysis revealed that the GaN-related peak for all the samples remained at its usual Bragg position of 2θ = 34.56°, whereas there was a shift in the AlInN peak from its position of 2θ = 35.51° for the as-grown samples. RBS analysis exhibited a shift in the position of the indium-related peak, indicating a migration of indium atoms towards the interface of heterostructures. Moreover, this peak was observed to split into two peaks, which is an indication of the depth-wise redistribution of indium atoms within the material. The measurements of magnetization versus temperature as well as the applied magnetic field performed using a SQUID magnetometer indicated the room temperature ferromagnetism in the materials. The density functional theory based calculations of TM-doped AlInN predicted that the dopant ions would preferably substitute In sites in the alloy.