Carnegie Laboratory of Physics, School of Engineering, Physics, and Mathematics, University of Dundee, Dundee DD1 4HN, United Kingdom.
Phys Rev Lett. 2010 Nov 26;105(22):226102. doi: 10.1103/PhysRevLett.105.226102. Epub 2010 Nov 23.
Cation vacancies on both sublattices (V(Ti), V(Sr)) have been identified in homoepitaxial pulsed laser deposited SrTiO3 films using high intensity variable energy positron annihilation lifetime spectroscopy (PALS) measurements. Film nonstoichiometry was varied by varying laser fluence. PALS showed that on increasing the fluence above the Ti/Sr∼1 value, the concentration ratio [V(Sr)]/[V(Ti)] systematically increased. Reducing the fluence into the Ti-poor region below resulted in additional vacancy cluster defect formation. Vacancy concentrations greater than ∼50 ppm were observed in all films.
采用高强度变能正电子湮没寿命谱（PALS）测量，在同质外延脉冲激光沉积 SrTiO3 薄膜中发现了两个亚晶格上的阳离子空位（V(Ti)，V(Sr)）。通过改变激光能量密度来改变薄膜的非化学计量比。PALS 表明，在将能量密度增加到 Ti/Sr∼1 以上时，[V(Sr)]/[V(Ti)]的浓度比系统地增加。在 Ti 贫区减少能量密度会导致额外的空位团缺陷形成。在所有薄膜中都观察到空位浓度大于 ∼50ppm。
