Pulsed Laser Deposition of Doped Lanthanum Gallate and In Situ Analysis by Mass Spectrometry of the Laser Ablation Plume

Abstract

Sr- and Mg-doped LaGaO3 powders with various dopant concentrations (La1-xSrxGa1-yMgyO3-(x+y)/2 where 0.02 ≤ x ≤ 0.2 and 0.02 ≤ y ≤ 0.2) were synthesized through a novel solution combustion route. X-ray diffraction patterns indicate orthorhombic structure for compositions 0 ≤ x ≤ 0.075 and 0 ≤ y ≤ 0.075 and primitive − cubic for 0.1 ≤ x ≤ 0.2 and 0.1 ≤ y ≤ 0.2. Thin films of La1-xSrxGa1-yMgyO3-(x+y)/2 (0.1 ≤ x ≤ 0.2 and 0.1 ≤ y ≤ 0.2) were deposited using both Nd:YAG (532 nm) and excimer (248 nm) lasers. The as-deposited films at room temperature were amorphous, which on annealing at 973 K exhibited single-phase cubic structure. Films deposited with excimer laser were smooth and particulate free compared to Nd:YAG laser deposition. The LSGM films on Si[111] and sapphire[0001] substrates showed good surface morphology compared to films on MgO[001] and amorphous quartz. Films were found to be slightly rich in Sr/La ratio compared to target composition. O+, O, Ga+, Ga, and La+ were the major species in the laser ablation plume with ion and neutral velocities of 3 × 105 and 3 × 104 cm/s, respectively.