Epitaxial Growth of Quasi-intrinsic CsPbBr₃ Film on a SrTiO₃ Substrate by Pulsed Laser Deposition

In this paper, inorganic halide perovskite cesium lead bromide (CsPbBr3) films are epitaxially grown on (100)-oriented SrTiO3 substrates by pulsed laser deposition (PLD). This method has the distinctive advantages to grow high-quality films with a precise composition, designed crystalline orientation, and controlled uniform thickness. By optimizing the substrate temperatures and laser pulse numbers, (100)-CsPbBr3 films with uniform morphology are grown on a SrTiO3 substrate via a cubic-on-cubic epitaxial growth mode, which is proven by XRD investigation. Detailed photophysical spectroscopy study including femtosecond transient absorption spectra and detailed low-temperature photoluminescence spectra indicate that such epitaxial CsPbBr3 films are of very low defects in the bandgap. The temperature-dependent resistivity measurement reveals that the epitaxial CsPbBr3 films show a typical thermally activated carrier behavior with a bandgap value of 2.37 eV, which is very consistent with the optical result and indicates a quasi-intrinsic semiconductor nature of such an epitaxial film. Our results confirm that CsPbBr3 films with high crystal quality and lower defect density can be epitaxially grown with PLD for further superlattices and quantum wells.