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

Sr- and Mg-doped LaGaO 3 powders with various dopant concentrations (La 1 - x Sr x Ga 1 - y Mg y O 3 - ( 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 La 1 - x Sr x Ga 1 - y Mg y O 3 - ( 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 × 10 5 and 3 × 10 4 cm/s, respectively.