Investigation of electrical and thermal transport property reductions in La-doped BaSnO3 films

The electron mobility value of 320 cm(2) V-1 s(-1) observed from La-doped BaSnO3 (LBSO) single crystals has a great potential in optoelectronic applications, but LBSO films exhibit much lower mobilities. Threading dislocations from the film/substrate mismatch are believed to be the main source of this phenomenon, but previous experiments suggest that they do not fully explain the mobility suppression. In this paper, we examined the thickness dependence of electrical and thermal transport properties of LBSO films fabricated in different oxidation environments. The results show that oxygen deficiency also affects the electron mobility of LBSO films, and the mobility suppression in LBSO films is dominated by different mechanisms depending on the thicknesses. LBSO films with different oxygen vacancy contents were fabricated using the pulsed laser deposition technique. The films deposited under higher oxidative conditions exhibited lower oxygen deficiency levels and superior transport properties whereas the threading dislocation densities remained unchanged. The highest mobility value observed in this paper was 120 cm(2) V-1 s(-1), which is comparable to LBSO films fabricated on thick buffer layers. Our paper provides a broader perspective on understanding the mobility of LBSO films and confirms that threading dislocations are not the only factor.