Ab initio calculations and experimental study of piezoelectric YxIn1−xN thin films deposited using reactive magnetron sputter epitaxy

Abstract

By combining theoretical prediction and experimental verification we investigate the piezoelectric properties of yttrium indium nitride (YxIn1−xN). Ab initio calculations show that the YxIn1−xN wurtzite phase is lowest in energy among relevant alloy structures for 0≤x≤0.5. Reactive magnetron sputter epitaxy was used to prepare thin films with Y content up to x=0.51. The composition dependence of the lattice parameters observed in the grown films is in agreement with that predicted by the theoretical calculations confirming the possibility to synthesize a wurtzite solid solution. An AlN buffer layer greatly improves the crystalline quality and surface morphology of subsequently grown YxIn1−xN films. The piezoelectric response in films with x=0.09 and x=0.14 is observed using piezoresponse force microscopy. Theoretical calculations of the piezoelectric properties predict YxIn1−xN to have comparable piezoelectric properties to ScxAl1−xN.