Excimer laser annealing of p-type perovskite thin films

The ability of excimer laser irradiation to anneal and to crystallize amorphous films of the p-type perovskite SrFeyCo1-yO2.5+x (y = 0.5) has been investigated. The films were prepared by the pulsed laser deposition technique on Si and sapphire substrates held at room temperature or 240 degreesC. Both film deposition and film annealing were carried out using a KrF excimer laser (lambda=248 nm). Films of SrFe0.5Co0.5O2.5+x deposited at room temperature on sapphire substrates have been crystallized with 160 laser pulses at 50 mJ/cm, while irradiation of a film deposited at room temperature on a Si substrate has resulted in its crystallization following 40 pulses at 100 mJ/cm(2). Films deposited at 240 degreesC have been crystallized with 480 and 320 pulses at 50 and 60 mJ/cm(2) respectively. The application of the excimer laser annealing technique permits the modification of film crystallinity after deposition, and because this can be achieved with a high degree of control of irradiation energy, this facilitates the integration of crystalline films of high melting temperature perovskites with substrates which have a low melting point.